Diamond Edge Polishing System When using diamond edge polishing, edges on acrylic sheets are moved over sharp, fast-rotating diamonds. Properly done is the result so good that diamond polishing can be compared with cast surfaces. Moreover, the method is relatively inexpensive and can be performed on large batches. Diamond edge polishing may be used on edges of shelves and signs that have previously been sawn to correct dimensions. It should be noted that diamond edge polishing is exclusively for straight or sloping sides. Eg. it cannot be used on rounded corners