Grit Guard Insert is a raised radial surface that fits in the bottom of any 3-5 gallon bucket and extracts grit from your wash mitt or sponge when the sponge is dragged across the Grit Guard. The dirt settles at the bottom of the bucket so wash water stays clean. The Grit Guards radial grid surface works by scraping dirt out of your mitt or sponge as four quadrants at the base of the Grit Guard calm the wash water and hold the grid at the bottom of the bucket. Dirt falls to the bottom and stays there. The Grit Guard is a real paint-saver and has a number of other uses, too. Use it to clean paint brushes by running the bristles across the grid in a bucket of water or paint thinner. Also use to clean automotive parts or drain your oil filter.