Fabric care, laundry and stain removal

In short

Fabric care covers every operation that keeps a textile serviceable after it is made: sorting, washing (by hand, machine or solvent), bleaching, stiffening, drying, pressing, stain removal and storage. The right treatment depends on fibre content, dye fastness, finish and construction - wool felts in hot alkali, silk yellows in chlorine bleach, and viscose loses up to half its strength when wet. It is examined in Home Science / Community Science B.Sc papers on textiles, clothing and consumer science, and in NET/SET and PG entrance tests; practically it underpins jobs in laundry and dry-cleaning chains, hotel housekeeping, hospital linen management, apparel quality control and consumer-affairs work. Care labelling, detergent quality and false claims are governed in India by BIS standards, the Legal Metrology (Packaged Commodities) Rules, 2011 and the Consumer Protection Act, 2019.

Explained

Why fibre and finish decide the care

• Cellulosics (cotton, linen): strong when wet (cotton gains about 10-20% strength), alkali-resistant, stand boiling and chlorine bleach; damaged by acids and prone to creasing and mildew if stored damp.
• Regenerated cellulose (viscose/rayon): loses 40-60% of its dry strength when wet, so it must never be wrung, rubbed or spun hard; handle flat and support the weight.
• Protein fibres (wool, silk): damaged by alkali, by chlorine bleach and by heat-plus-agitation. Wool felts (irreversible shrinkage) because its scaly surface ratchets together under friction - wash cool, with minimal movement, and use a neutral or mildly acidic detergent.
• Synthetics (polyester, nylon, acrylic): hydrophobic, dry fast, need little or no ironing, but hold oily soil strongly, build static, pill, and are heat-sensitive - nylon and acrylic soften at low ironing settings; polyester attracts redeposited grey soil.
• Finishes: resin/durable-press, water-repellent, flame-retardant and coated fabrics can be destroyed by strong alkali, chlorine bleach or high heat; a flame-retardant finish is often disabled by soap and by hard water.
• Dye fastness: poor wash fastness causes bleeding and crocking; test an inconspicuous corner, wash dark lots separately, and use cool water with salt or vinegar only as a palliative, not a cure.

Care labelling and the five symbols

• A care label carries fibre content, country of origin and care instructions. ISO 3758 is the international care-symbol standard that Indian exporters and most domestic brands follow; the symbol set has five elements in a fixed order.
• Washtub - washing: a number is the maximum temperature in °C; one bar under the tub means mild (reduced) action, two bars very mild, a hand in the tub means hand wash only, a crossed tub means do not wash.
• Triangle - bleaching: plain triangle = any bleach allowed; two diagonal lines inside = oxygen bleach only; crossed = do not bleach.
• Square - drying: a circle inside is tumble drying (one dot low heat, two dots normal, crossed = do not tumble dry); lines inside the plain square show line dry (one vertical line), drip dry (two vertical lines) or flat dry (one horizontal line).
• Iron - pressing: one dot ≈ 110 °C (acrylic, nylon, acetate), two dots ≈ 150 °C (polyester, wool, silk), three dots ≈ 200 °C (cotton, linen); crossed = do not iron; crossed steam lines = no steam.
• Circle - professional textile care: P = dry clean with perchloroethylene and hydrocarbons, F = hydrocarbon solvent only, W = professional wet cleaning, a bar = mild process, crossed = do not dry clean.
• Indian practice: the declarations required on pre-packed garments by the Legal Metrology (Packaged Commodities) Rules, 2011 are the manufacturer/packer/importer name and address, size or net quantity, MRP, consumer-care details and (for imports) country of origin - fibre composition is a labelling convention and buyer requirement rather than a declaration under those Rules; whether care symbols themselves are compulsory for domestic sale has varied with ministry orders, so a note that the symbols are followed as standard practice is safer than claiming a blanket legal mandate.

Detergents, water and what each ingredient does

• Soap is the sodium salt of a fatty acid; in hard water its calcium and magnesium salts are insoluble and deposit scum on the fabric (grey, stiff, dull handle). Synthetic detergents (syndets) are petro- or oleo-chemical surfactants whose calcium salts are soluble, so they work in hard and even slightly acidic water.
• Surfactant action: the molecule has a hydrophobic tail and hydrophilic head; it lowers surface tension so water wets the fabric, then emulsifies oily soil, suspends particulate soil and keeps it from redepositing. Classification: anionic (LAS, soap - main cleaners), non-ionic (low foam, excellent on oily soil, used in liquids and front-load powders), cationic (poor cleaners, used as fabric softeners), amphoteric (mild, personal-care).
• Builders (sodium carbonate, silicates, zeolite A, citrates, formerly STPP) sequester hardness ions, hold alkalinity (pH about 9-10.5) and improve soil dispersion. Phosphate use has been cut back because it causes eutrophication.
• Other actives: CMC (anti-redeposition), enzymes - protease for blood/egg, amylase for starch, lipase for fats, cellulase for pilling and colour clarity (all are inactivated by hot water and chlorine bleach); optical brightening agents (fluorescent whitening agents) absorb UV and re-emit blue light so whites look whiter without removing soil; sodium perborate/percarbonate as oxygen bleach; perfume, fillers (sodium sulphate), foam regulators.
• Water hardness is expressed as mg/L (ppm) of CaCO₃; soft below 60, moderately hard 60-120, hard 120-180, very hard above 180. Hard water wastes soap, dulls colours and leaves deposits; soften by boiling (temporary hardness), washing soda, zeolite/ion exchange or by using syndets.
• BIS standards: IS 285 covers household laundry soaps and IS 4955 covers household laundry detergent powders; detergent bars and liquids have their own specifications. These are quality specifications, not blanket mandatory certifications - check the current list of mandatory items before asserting ISI marking is compulsory.
• Soft water (drinking-quality) and SI units matter in exam numericals: dose rates are quoted in g detergent per litre of liquor or per kg of dry load.

The laundry process, step by step

1. Collect and check: empty pockets, close zips, mend tears first (washing enlarges them), note stains and treat them before washing - heat sets most stains permanently.
2. Sort by colour (white / light / dark), fibre and care code, soil level, construction (lint-givers vs lint-takers) and by required water temperature.
3. Pre-treat: soak heavily soiled cottons in detergent solution 15-30 minutes (never soak wool, silk, coloured or non-fast items for long); apply a paste or spotting agent to collars and cuffs.
4. Wash: the four variables are mechanical action, chemical action, temperature and time - the "Sinner's circle"; reduce one and another must rise. Methods: friction (rubbing/brushing - sturdy cotton only), kneading and squeezing (wool, silk, viscose), suction washing, machine washing (top-load agitator/impeller, front-load drum which is gentler and uses less water).
5. Rinse: at least two to three changes of water until no foam remains; residual alkali yellows fabric on ironing and irritates skin. Final rinse may carry a softener, blue or starch.
6. Hydro-extract: squeeze or spin; wool and viscose are rolled in a towel, never wrung.
7. Dry: line dry cottons and linens in sun (sun bleaches and disinfects whites); dry coloureds and silk in shade to avoid fading; dry wool and knits flat to avoid stretching; tumble dry only where the label permits.
8. Finish: starch or stiffen, then iron at the correct temperature on the right side or wrong side (silk, dark colours, satin, embroidery from the wrong side over a cloth), then air, air and store.

Bleaching, stiffening, blueing and softening

• Bleaching removes colour from stains and yellowing by oxidation or reduction - it is a last resort because it also attacks the fibre.
• Oxidising bleaches: sodium hypochlorite (strong, cottons/linens only, never wool, silk, nylon, spandex or resin-finished goods; excess leaves chlorine that tenders cotton on ironing - neutralise with sodium thiosulphate); hydrogen peroxide and sodium perborate/percarbonate (mild, safe for wool and silk at low temperature, slower, need warmth to work).
• Reducing bleaches: sodium hydrosulphite (hydros), sodium bisulphite - good on stripping dyes and on reduced-type stains; whiteness can revert on exposure to air.
• Sunlight and moisture (grassing/crofting) is the traditional, gentlest bleach for cotton and linen.
• Stiffening agents: rice, maize, arrowroot and sago starch (cooked; cotton and linen), gum arabic and gelatine (silk, non-boilable), borax (silk, wool, light stiffness), PVA-based synthetic stiffeners and sprays. Hot starch for thick cottons, cold/thin starch for muslins and voiles.
• Blueing is a complementary-colour trick: a trace of blue pigment (ultramarine or an acid blue) absorbs yellow light so the fabric reads neutral white. Only for whites, applied evenly in the final rinse - streaks and over-blueing give a grey-blue cast.
• Fabric softeners are cationic surfactants that deposit on fibres to reduce friction and static; they reduce absorbency, so avoid on towels, nappies and microfibre.

Stain removal: principles and classified methods

• Golden rules: identify the stain and the fibre; act immediately; blot, never rub; work from the wrong side, inwards from the edge of the stain towards its centre, on an absorbent pad so the stain is pushed out without leaving a ring; use the mildest effective agent first (cold water → detergent → absorbent → solvent → chemical); test on a hidden seam; rinse thoroughly between agents; never use hot water on protein or unknown stains; never mix chlorine bleach with ammonia or acids.
• Methods: (i) dip/immersion for small items, (ii) steam/kettle method for fast-dyed cottons, (iii) absorption with French chalk, talc, starch or fuller's earth for grease on non-washables, (iv) sponging/spotting with solvent, (v) chemical bleaching, (vi) enzyme digestion for protein and starch.
• Classification by nature:
  • Animal/protein (blood, egg, milk, perspiration) - cold water and detergent or enzyme soak; heat coagulates and sets them; ammonia or hydrogen peroxide for residue.
  • Vegetable/tannin (tea, coffee, fruit, wine, turmeric) - hot water on cottons, borax or lemon juice, oxygen bleach; soap first can fix fruit stains. Turmeric responds to sunlight and alkaline soap-then-rinse.
  • Grease/oil (ghee, butter, oil, lipstick, machine oil) - absorbent powder, then a grease solvent (white spirit, dry-cleaning fluid) or hot detergent with non-ionic surfactant.
  • Dye stains (ink, ballpoint, mehndi, curry, colour bleeding) - solvent for ballpoint, reducing bleach or colour remover as last resort.
  • Mineral/metallic (iron rust, mildew, hard-water marks) - oxalic acid or lemon juice with salt for rust (never bleach - it darkens rust); mildew needs peroxide plus sunlight, and prevention by dry storage.
  • Combination (curry, cosmetics, gravy, paan) - remove the grease part with solvent first, then the dye/tannin part with water-side treatment.
• Dry cleaning: cleaning in an organic solvent with 0.5-2% detergent and a trace of water (charged system), used for wool suits, silks, structured and non-washable garments; stages are pre-spotting, cleaning in solvent, filtration/distillation of solvent, extraction, drying/deodorising, post-spotting and pressing. Perchloroethylene (PCE) is the classic solvent but is being replaced by hydrocarbon, siloxane (GreenEarth), liquid CO₂ and professional wet cleaning on health and environment grounds; PCE is a listed hazardous chemical and spent solvent/still residue is hazardous waste under the Hazardous and Other Wastes (Management and Transboundary Movement) Rules, 2016.

Storage, pests and institutional practice

• Store only clean, completely dry and starch-free articles - starch and food residues attract silverfish and cockroaches; damp causes mildew.
• Wool and silk pests: clothes moth larvae and carpet beetle eat keratin. Control by brushing and sunning, airtight storage, naphthalene or paradichlorobenzene balls (volatile, keep away from plastics), neem/camphor, and cedar; mothproofing finishes exist on carpets.
• Fold heavy knitwear and wool flat rather than hanging (hangers stretch them); use padded hangers for tailored garments; interleave zari and silk with acid-free or unbleached muslin, never direct contact with plastic or newspaper print.
• Institutional laundry (hotels, hospitals, railways) uses a classical multi-bath cycle: flush → break (high-alkali) → suds → bleach → rinses → sour (acid neutraliser, pH down to about 5-6) → softener/starch → extraction → tunnel finishing. Hospital linen requires thermal disinfection (typically 71 °C for 3 minutes or 65 °C for 10 minutes in the wash, as per infection-control guidance) and strict segregation of infected linen.
• Workers handling solvents and hot equipment are covered by the occupational safety and welfare provisions of the Occupational Safety, Health and Working Conditions Code, 2020 (in force 21 November 2025, replacing the former Factories Act, 1948), and effluent discharge by the State Pollution Control Board consent under the Water (Prevention and Control of Pollution) Act, 1974.

Key points

• Sinner's circle - cleaning = mechanical action + chemical action + temperature + time; cut one and compensate with another.
• Soap vs detergent - soap forms insoluble scum in hard water; syndets do not and work in acidic and hard water.
• Surfactant - lowers surface tension, wets, emulsifies and suspends soil; anionic cleans, cationic softens, non-ionic handles oily soil.
• Builder - sequesters Ca²⁺/Mg²⁺ and supplies alkalinity; zeolite and citrate replaced phosphates to curb eutrophication.
• Enzymes - protease (blood), amylase (starch), lipase (fat), cellulase (pilling); killed by hot water and chlorine bleach.
• Optical brightener - converts UV to blue light, makes whites look whiter; it masks yellowing, it does not clean.
• Blueing - adds trace blue to neutralise yellow by colour subtraction; for whites only.
• Wool felting - friction plus heat plus alkali locks the scales; hence cool water, no rubbing, neutral detergent.
• Viscose when wet - loses 40-60% strength; support it, never wring or hang heavy.
• Chlorine bleach - cottons and linens only; destroys wool, silk, nylon, spandex and resin finishes.
• Oxygen bleach - hydrogen peroxide/perborate/percarbonate; mild, colour-safe, works better warm.
• Heat sets stains - always cold water first for blood, egg, milk and any unidentified stain.
• Grease-plus-dye stains - solvent first for the oil, then the water-side treatment for the dye.
• Rust - oxalic acid or lemon and salt; chlorine bleach darkens it.
• Care symbols - tub (wash), triangle (bleach), square (dry), iron (press), circle (professional care); dots = temperature, bars = milder process, cross = prohibited.
• Dry cleaning - organic solvent plus 0.5-2% detergent and trace water (charged system); PCE giving way to hydrocarbon, siloxane, CO₂ and wet cleaning.
• Sour - acid rinse in institutional laundry to neutralise residual alkali and prevent yellowing on pressing.
• Storage - clean, dry, starch-free, dark and ventilated; moths attack protein fibres, mildew attacks damp cellulosics.

Formulas and examples

Example 1 - Detergent dose and concentration. A front-load machine takes a 6 kg dry load. The pack says 25 g/kg for normally soiled clothes in hard water, and the wash liquor is 45 L.

• Dose = 25 × 6 = 150 g.
• Concentration = 150 ÷ 45 = 3.33 g/L.
• If the water were soft and the recommended rate dropped to 18 g/kg, dose = 18 × 6 = 108 g, a saving of 42 g per wash. Over 150 washes a year that is 6.3 kg of detergent; at ₹140/kg it is about ₹882 a year.

Example 2 - Liquor ratio in hand washing. A student washes 1.5 kg of cotton clothes in a bucket holding 18 L of water.

• Liquor ratio = 18 ÷ 1.5 = 1:12.
• At 3 g/L, detergent needed = 3 × 18 = 54 g, i.e. 36 g per kg of cloth - far more than a front-loader needs, because a wide liquor ratio dilutes the same chemistry. Three rinses of 18 L each add 54 L, so the full wash uses 72 L for 1.5 kg, i.e. 48 L/kg.

Example 3 - Shrinkage after the first wash. A cotton kurta is marked 108 cm long and 56 cm across the chest. After one hot wash it measures 103.5 cm and 54.9 cm.

• Length shrinkage = (108 − 103.5)/108 × 100 = 4.5/108 × 100 = 4.17%.
• Width shrinkage = (56 − 54.9)/56 × 100 = 1.1/56 × 100 = 1.96%.
• Length shrinkage above about 3% is usually judged unacceptable for a fitted garment; the remedy is to buy pre-shrunk/sanforized fabric or allow extra length at the stitching stage.

Example 4 - Hypochlorite bleach dilution. A bleach solution contains 4% available chlorine (40 g/L). A 10 L wash bath needs 200 ppm available chlorine.

• Chlorine required = 200 mg/L × 10 L = 2,000 mg = 2 g.
• Volume of bleach = 2 ÷ 40 = 0.05 L = 50 mL.
• To neutralise afterwards, a dilute sodium thiosulphate rinse is used; the bath must be cool and the goods pure cotton - the same 200 ppm would yellow and tender silk or wool.

Example 5 - Laundry cost comparison. Washing a woollen blazer: dry cleaning at a city chain costs about ₹250-400 per piece (rates vary by city and brand), while home hand-washing in a wool-safe detergent costs roughly 30 g detergent (₹6), 40 L water (₹0.08/L = ₹3.2) and no electricity - about ₹9 plus 30 minutes of labour and a real risk of felting or distortion if the structured garment is immersed. The economics favour home care for knitwear and dry cleaning for tailored, lined and interfaced garments.

Where it is used

• Laundry and dry-cleaning services: 5àsec, Tumbledry, UClean, Pressto and thousands of local units - roles in spotting, solvent handling, pressing and process supervision.
• Hotel and hospital housekeeping: linen and uniform management, par stock, OPL (on-premise laundry) chemistry, infected-linen protocol - large employers include Taj, Oberoi, Marriott and hospital chains like Apollo and Fortis.
• FMCG detergent and home-care companies: HUL (Surf Excel, Rin, Wheel), P&G (Ariel, Tide), Nirma, Jyothy Labs (Ujala blue, Henko), RSPL (Ghadi) - roles in product development, consumer testing and claim substantiation.
• Apparel export houses and testing labs: wash-fastness, dimensional stability and care-label compliance for buyers; labs like SGS, Intertek, TUV, Bureau Veritas and the Textiles Committee run ISO 105 and ISO 6330 tests.
• Consumer affairs and extension work: teaching care labelling and detergent choice, grievance redress under the Consumer Protection Act, 2019, and consumer-awareness programmes by the Department of Consumer Affairs.
• Museum and heritage textile conservation: zari, Kanjeevaram, Paithani and Pashmina care at institutions such as the National Museum and the Calico Museum, Ahmedabad.

Interview questions

• Q: Why does soap not clean well in hard water? A: Calcium and magnesium ions precipitate the fatty-acid anion as an insoluble scum, so soap is consumed before it can clean and the scum deposits on the fabric as a grey, stiff film.
• Q: What does a builder do in a detergent? A: It sequesters hardness ions, maintains alkaline pH for soil removal and helps keep soil dispersed, so a smaller amount of surfactant works harder.
• Q: Why must blood and egg stains be treated with cold water? A: They are protein stains; heat coagulates the protein onto the fibre and sets the stain permanently.
• Q: Why is chlorine bleach forbidden on wool and silk? A: Hypochlorite attacks the peptide and disulphide bonds of protein fibres, causing yellowing, harshness and severe strength loss.
• Q: What is the difference between blueing and optical brightening? A: Blueing adds a trace of blue pigment that absorbs yellow light; an optical brightener is a fluorescent dye that converts invisible UV into visible blue light - neither removes soil.
• Q: Why is wool washed without rubbing? A: Friction with heat and alkali makes the surface scales interlock, producing irreversible felting shrinkage.
• Q: How do you tackle a curry or cosmetic stain? A: Treat it as a combination stain - lift the oil with an absorbent or solvent first, then remove the remaining dye or tannin with detergent and an oxygen bleach.
• Q: What does the circle with a P on a care label mean? A: Professional dry cleaning with perchloroethylene and hydrocarbon solvents is permitted; a bar under it means a mild process, and a crossed circle means do not dry clean.
• Q: What is a charged system in dry cleaning? A: Solvent with about 0.5-2% dry-cleaning detergent and a controlled trace of water, so water-soluble soil and salts are removed along with the oily soil the solvent dissolves.
• Q: Why does a viscose dress distort after a machine wash? A: Viscose loses a large part of its strength when wet and the swollen fibres stretch under the load of water and spinning; it should be squeezed flat, not wrung or spun hard.
• Q: Why is an acid "sour" rinse used in hotel laundries? A: It neutralises residual alkali from the break and bleach baths, preventing yellowing and fibre tendering during pressing and reducing skin irritation.
• Q: Why do towels feel less absorbent after using fabric softener? A: The cationic softener deposits a hydrophobic film on the fibre surface, which reduces wicking and water uptake.

Common mistakes

• Writing that higher temperature always cleans better - heat sets protein stains, kills enzymes, felts wool and softens heat-sensitive synthetics.
• Reaching for chlorine bleach as a general whitener instead of distinguishing oxidising, reducing and oxygen bleaches and their safe fibres.
• Confusing blueing with bleaching, or an optical brightener with a cleaning agent.
• Rubbing a stain or working from the face of the fabric, which spreads the ring and abrades the surface instead of pushing the stain out from the wrong side.
• Mixing chlorine bleach with ammonia or an acid - this releases toxic gas; and using bleach on rust, which darkens it.
• Soaking coloured, woollen or silk items for long periods, or soaking before stain treatment so the stain is fixed.
• In exams, misreading care symbols - dots mean temperature, bars mean a milder mechanical action, and a cross means prohibited; and quoting withdrawn Indian Standard numbers instead of naming the standard's subject.

Related topics

Textile fibres: natural and synthetic · Dyeing, printing and textile finishes · Consumer protection and consumer education · Household equipment and home management · Housekeeping and institutional linen management · Textile testing and quality control