Shrinkage is not something you desire when you wash a dance belt, but getting it clean is a good thing. I stuff mine in the machine on the COLD setting and they seem to last forever without problems. I use a standard model detergent, no bleach, and no softner.
Never try to dry a dance belt in the dryer! All you can do is create problems. Hang drying avoids shrinkage and other heat damage.[/i]