Well the pink styrofoam will actually not melt from the glow fuel, it just soaks in, the varathane i suggested above will seal the foam and also allows you to use spray paint that would eat the foam if there was no sealer, i usually use 2 coats of the varathane before spraying. The varathane dries clear-kinda cloudy so you could put this over the white foam and it will still look white.