Make sure you wash separately. Zippers on jeans are especially damaging to dance and gym wear.
Wash inside out separately in a large volume of cold water on gentle cycle. Must use a very mild liquid detergent. Do not use bleach, harsh or granular detergents, Woolite or liquid fabric softner. Remove immediately from wash and hang to dry. Do not dry clean. Do not iron.
Proper laundering of your dance and gym wear will insure that it maintains color, fabric characteristics and fit. You will enjoy you dance and gym wear and get a lot more out of it if you wash it correctly.