These discs are great for polishing up your metal pieces without a tumbler and saving the elbow grease of doing it by hand. The discs go on a 3/32" screw mandrel, all 3 at a time. Work from red up to pink to get that mirror finish desired. You want to work: red, blue, pink, peach, light green. Some may opt to skip the red. If you already did a good bit of sanding in the greenware stage, skip the red and start with the blue. As you work through each color, for just 10 or so seconds, you'll remove scratches and make the surface more uniform.