polystyrene densifier Mars series adopt hot-melt technology. The small polystyrene pieces cut by the crusher will then be heated to 190 degrees Fahrenheit which turns the polystyrene into a soft pliable material that can be densified into a denser form at a ratio of 90:1. INTCO Recycling Supply polystyrene foam densifier M-C300 for polystyrene foam recycling and Buy Back Foam Blocks. Applicable materials include EPS, EPP, PSP, XPS, PSP/food trays, and cups.