Things You'll Need
3 clean rags
Polystyrene is a thermoplastic material which is solid at room temperature. As a solid, polystyrene plastic is colorless and hard. It is a versatile plastic with many applications. When heated polystyrene becomes liquid and can be molded into plastic objects of different shapes and sizes. Polystyrene plastic can be found in many products from Styrofoam cups and disposable cutlery to DVD cases and vehicle headlights. Polishing polystyrene plastic not only removes dirt but also returns its original sheen.
Pour some water in a large bowl.
Add a tbsp. of dish-washing soap to make a soapy solution.
Dip a rag in the soap solution. Clean the surface of the plastic with the rag. Make sure to scrub hard so as to remove all dirt, dust and grease.
Soak a few sandpapers in water. Make sure the sandpapers are of different grits (for example, 200, 400, 800 to the finer 2000 grits.) Sandpapers should only be used on transparent or translucent polystyrene plastic especially those used in screens and in headlights.
Sand the surface of the plastic gently with the wet sandpapers. Start with the lowest (200 grits) and sand with the finest last. Allow the surface of the polystyrene plastic to dry.
Apply a coat of plastic polish to the surface of the polystyrene with a rag. Buff the waxy polish on the plastic surface using the rag.Allow the polish to dry on the polystyrene plastic.
Wipe down the polystyrene plastic with a second clean rag. This second buffing will remove excess waxy polish and restore the sheen on the plastic.