Because Corian sinks and countertops are a single, solid surface--unlike most countertops, which have a finish layer on the surface--you can repair scratches or surface mottling and restore the original lustre without refinishing. Minor dings and dents may happen despite diligent cleaning and maintenance. But buffing and sanding Corian restores its original finish by revealing the undamaged surface beneath the flaws.
Scrub gently with solid surface cleaner and a soft sponge. Wipe with a wet rag and dry completely with a dry rag or paper towels. If the Corian needs additional cleaning, apply deep cleaning spray, then wipe off and dry. Use hard water stain remover to get rid of water marks, then rinse and dry.
Pour a squirt of mildly abrasive liquid cleanser on a sponge and rub it on gently in overlapping circles to fix small scratches or blotchy patches. Wipe the cleanser off with a wet rag and dry. If the scratches and blotches remain, use more cleanser and increased pressure. Wipe off and dry.
Dampen the countertop or sink around burn marks or other minor flaws with a wet rag. Rub gently in overlapping, vertical and horizontal motions with the coarsest pad in your solid surface countertop repair kit or 400-grit wet sandpaper. Rinse the pad or paper as needed.
Blend the sanded area in by sanding a larger area with a finer pad from your repair kit or a finer grit of sandpaper. Wipe and dry.
If you do not have solid surface cleaner, an ammonia-based household cleaner (not window cleaner) will work. Do not use harsh chemicals or acid-based cleaners on Corian. For disinfecting, wipe the surface with a solution of one part bleach and one part water. Wipe it off with a wet rag and dry. Prevent damage by wiping up spills quickly, drying the countertop every time it gets wet, using only approved cleaners and soft sponges to clean it and using a trivet under hot dishes.
Some scratches, dents or burns may require professional repair. If you cannot restore a flaw despite multiple attempts, call a professional contractor with experience in Corian repair. Further attempts and increased pressure may cause bigger problems.