Colored polystyrene closed-cell foam will dissolve in polystyrene resin, styrene, gasoline, acetone and a million other solvents. Polyurethane foam will not.
More than this gets more involved.
PS: If you ever get to Florida, stay away from Bill Roberts who might want to punch you in the eye. (Thats a joke- he wouldn't really)

Dacarls:
A-class USA 196, USA 21, H18, H16
"Nothing that's any good works by itself. You got to make the damn thing work"- Thomas Edison