John mentions soaking in Methylated spirits to remove dop wax. A method
that works well for me is to set the dopped stone in the freezer
compartment of the fridge for 10 - 15 min. The stone pops off and leaves
only a small amount of residue which is easily removed with a little
solvent on a rag. I use denatured alcohol instead of methylated spirits on
the rag. On these hot, muggy days, I might use a little 5% ethyl alcohol
applied internally while the stone freezes.
In Wisconsin - Midwest USA