A care label tells you what a specific garment can take. Knowing how the fiber itself behaves tells you why, and lets you make a sensible call when a label is missing, faded or in a language you don't read. The label always wins when it's there; this is the reasoning behind it.
Hardy and heat-tolerant, which is why towels and bedding are cotton. It shrinks on its first wash if it wasn't pre-shrunk, mostly in hot water and a hot dryer, so wash new cotton cool the first time. Labels usually allow warm or hot water for whites and a medium dryer setting. Cotton creases easily and irons well at a hot setting with steam.
Strong and cool to wear, and it gets softer with every wash. Wash cool or warm on a gentle cycle, don't overload, and expect creases — they're part of the fabric. Tumble on low and remove while damp, or line dry, and iron while still slightly damp at a hot setting.
Wool's surface is scaly, and heat, water and agitation together lock the scales into each other: that's felting, and it's permanent. Wash cold on a wool or hand-wash cycle with a wool detergent, never tumble unless the label explicitly allows it, and dry flat. Superwash-treated wool is more forgiving but still prefers cool water. Our guide to washing wool and delicates goes through the method step by step.
Everything that applies to wool, more so. Hand wash in cool water, squeeze rather than wring, dry flat and reshaped. Pilling is normal and combs off.
A protein fiber like wool, weaker when wet and easily marked by water spots and sunlight. Many silks are labeled dry clean only because their dyes aren't stable in water. Washable silk wants cold water, a silk detergent, a mesh bag on the delicate cycle or a gentle hand wash, no wringing, drying away from direct sun, and a cool iron on the reverse while slightly damp.
Tough, quick-drying and shrink-resistant, but it holds onto body odor and oils, and high heat can set creases permanently or glaze the surface. Wash warm or cool on the synthetics cycle, add an extra rinse if sportswear smells after washing, and tumble on low or line dry. Iron cool if at all.
Similar to polyester: wash cool, tumble low, iron cool. It builds static in the dryer and can yellow with chlorine bleach or high heat.
Used as a wool substitute in knitwear. It pills readily and can stretch or go stiff with heat, so wash cool on a gentle cycle, turn inside out, and dry flat or on low.
Made from plant cellulose, and much weaker wet than dry: viscose in particular can shrink, stretch or lose its shape in a machine, which is why so much of it is labeled dry clean only. When the label allows washing, use cold water on the delicate cycle, don't wring, and dry flat, reshaping while damp. Lyocell and modal are more stable than viscose but deserve the same gentleness.
Heat destroys stretch. Anything with elastane — leggings, swimwear, stretch jeans, sportswear — wants cold water, a gentle cycle and no hot dryer. Fabric softener coats the fibers and can reduce both stretch and moisture-wicking.
Cotton, but with indigo dye that sits on the surface and rubs off. Wash inside out, cold, on its own or with other darks, as rarely as you can stand, and hang to dry — a hot dryer is what shrinks and fades jeans fastest. See how often to wash your clothes for the case against weekly jeans washing.
Treat a blend by its most delicate component. A cotton-elastane T-shirt is an elastane garment as far as heat is concerned; a wool-polyester suit is a wool garment. The label will already reflect that — it's why a mostly-cotton garment can carry a cold-wash symbol.
Every symbol you'll find on any of these labels is explained in the laundry symbol guide. LaundryMax reads them for you and keeps each garment's instructions in your closet. See how it works.