Plastic and uremic abrasive stones have lower density and are softer than ceramic stones. They are produced in conical, pyramidal and elliptical shapes. Plastic abrasive wheels are mostly used for deburring, degreasing, corner breaking, oxide removal of soft metal (aluminium, zinc brass, zinc alloy, gold, copper, silver etc.) and plastic based materials. There are many types in different sizes and shapes according to the shape of the part, sieving condition and desired precision.