SPRAY PAINT FOR BLACKING OUT STYROFOAM in AIR-CONDITIONER.

Anyone know what brand or kind of black spray paint will not melt the foam in my air-conditioner?

All solvent spray paints (aerosol cans) will melt styrofoam. Could you apply black tape over it instead of paint? Paints specifically for plastic MAY work, but I've never tried, they might have adhesion promoters in them that could adversely affect styrofoam. Or just get a brush on latex based paint.