My white Corian sink has a small gray spot, size of a rice grain that surfaced some time after I placed a small hot pot in sink. Around this spot I'm beginning to see another light gray spot too. In my excitement of burning boiled eggs(!), I placed the pot in the sink momentarily, then remembered to cool the pot on the stove. Can this spot be repaired? Can I do it? Many thanks!

You can sand Corian all you want, but there's no way to know how deep the discoloration is.

Ah! This one is right up my alley. I used to run a CNC machine for a Corian counter maker and in doing so, I got to learn much about Corian and how to fix it. Depending on the depth of this mark, you could possibly sand it out yourself. You would start with an 80 grit paper and sand evenly until you were satisfied with how the mark came out. Then you would switch to a 180 grit paper to smooth out the sanding marks from the 80 grit. When you are satisfied that it all looks good, you take a Scotch-Brite pad and do the whole sink with it. That will solve most problems.

If you are unsure about attempting it or your efforts don't work, any competent place that deals with Corian will be able to send someone out to repair it for you... probably the place you got your top from can do this. If it's Home Depot or Lowe's, they will be able to get someone to do it for you. The mark may need to be drilled out and plugged if it's deep enough but don't worry, if it's done right, you'll never be able to tell it's there.