Go to your local pool store and ask for clear adhesive liner patches. They come 5 x7, ina pack of 4 for like $6.00 . It will peal right off when you want to remove it.
As for clean up. Tar and bug remover I think its by Turtle wax. Mineral spirits should work .
Carbon is potted in epoxy. Once it is cured thats it, it wont soften, or melt. Unless you are Cleaning it with a strong acid.