The Cape Dory Board

I would like to redo my portlight gaskets and I read that many of you use the McMaster-Carr #8605K44 1/2" EPDM foam rubber as replacement. As this comes in 100' rolls, I am hoping to find someone with about 20' extra that they will part with for a reasonable price.

We have just purchased a CD 25D with original curtains, which are in great condition, but appear to have never been cleaned. The dry cleaners won't touch them. Does anyone know how we can clean them ourselves without damaging them?