I have a bathroom washbowl made of corian. It's 25 years old and has become crazed (has shallow cracks) around the drain and is stained brown. I've tried bleach on the stains, but it doesn't work. Can the crazing and stains be removed?

This may help you if your handy.

Ref:

Best Way - Do It Yourself Corian Countertop Repair | eHow.com

Is this a solid Corian top and sink or is the sink and under mount. Sounds more like some of the acrlic sinks I have replaced for folks, no saving acrylic when it starts to craze.