To polish most types of acrylic, fine grit sandpapers are the best option alternating between wet and dry to help them look like new. Using a piece of damp, 800 grit sandpaper in a buffing motion gently sand the surface before repeating with a dry piece of the same sandpaper. Keep alternating between the wet and dry pieces, rubbing for two to three minutes at a time. If it begins to look frosty this is just part of the process and these will disappear during the sanding. Move onto the grade 1200 paper and continue with the circular buffing motions, before drying to area fully with a soft, dry cotton cloth.