Where can I find Corian refinishing kit?

The manufacturer doesn't recommend heavy sanding. This is a care guide from the manufacturer (DuPont). Please read through it carefully. If you are having a major problem, I would suggest contacting them directly and speaking with someone there about your particular problem.

Care & Maintenance (http://www2.dupont.com/Surfaces/en_US/products/corian/corian_care.html)