In general, dry cleaning protects the life and wear of the garment better than machine, or sometimes hand, washing. HOWEVER, that said… almost everything can actually be machine washed, but that may shorten the lifespan and diminish the quality of your garment.
Acetate
Dry cleanable, do not soak colored items, do not twist/wring, machine wash separately or hand wash in warm water, iron on reverse side.
Cotton
Plain weave – Machine washable, bleachable if white, hot/warm iron, dry-cleanable, tumble dry.
Embroidered – Cool hand wash or dry-clean. Machine washing may cause puckering.
Laces / Jacquards
Dry clean only. Be careful, some of these fabrics are delicate, so be mindful of snagging and fraying on rough surfaces. Can hand wash laces with a delicate detergent like Woolite – but that will wash out any sizing that is in the lace and so may dramatically soften the drape. Jacquards may be hand washable – depending on the fiber content. Test a scrap to see, see this list for fiber care recommendations.
Linen
Can be machine washed and put in the dryer, but that may shorten the life of your garment and cause some color-fading. Press with a hot iron when you first buy, BEFORE washing to help set the sizing and minimize future creasing. Dry-cleaning is recommended for preserving the life and color of the garment.
Nylon / Polyester
Cold machine wash, tumble dry on low temperature, cool iron, dry cleanable, do not bleach.
Silk
Dry-clean only. Do not bleach, do not tumble dry, drip dry in shade. Warm iron. Can hand or machine wash at your own risk, using Woolite or silk detergent. Please note that this often DOES change the hand of the fabric – charmeuse becomes more sueded. Test on a scrap first. If you do decide to wash, ball up tightly and submerge in lukewarm or cool water all at once, vigorously ‘smushing’ it to make sure the water gets everywhere and there are no air pockets – which could cause water-spotting.
Rayon / Viscose
Dry-clean, cool machine wash, or hand wash. Do not twist/wring, iron on reverse side.
Tencel / Lyocell
Cold machine wash, tumble dry on low temperature, cool iron, dry cleanable, do not bleach.
Velvet
Dry clean only. Do not spot clean. Never iron as ironing is likely to crush or flatten the natural pile. A hand-held steamer can be used to remove creasing. Alternatively, hang your fabric or garment in a steamy bathroom as the steam may help relax any creasing. Velvet garments are best kept hanging, rather than folded. Avoid using clip hangers as these can bruise or mark the fabric. An effective cleaning technique I learned in China is to turn the garment inside out and mist the backside of the fabric thoroughly with plain water until the water goes through to the front side of the fabric. Turn back to the front side and use your hand or a garment brush to brush the surface lightly, this removes soiling. This technique is safe to use for spot cleaning and can even be used on embellished velvets.
Wool
Dry-clean, steam when pressing, brush wool to remove surface soil. Can hand wash in cool water, use Woolite detergent or similar specialty product.