ORIGINAL: Pydpiper

Carbon has a way of melting it's self into blocks.. The range I shoot at uses a Styrofoam block, they melt in every time. A shot of silicone spray or furniture polish helps a lot.
The sales guy said that warranty is hard to claim, the small print says each red dot must be completely gone and a few other stipulations. He also said it is a very tough block to begin with, not much chance of destroying it..