Car Care Products - Grit Guard - Black Description The main reason for paint swirls is improper detailing techniques. When you wash your vehicle, dirt and sand get trapped in the sponge or mitt. The first time you re-wet your sponge in the bucket, some of the abrasive particles will come off the sponge into the water. Subsequent dips in the bucket will re-contaminate your sponge. These contaminants will then rub against your paint and produce swirls. Grit guard helps to settle the dirt at the bottom of the bucket so your wash water stays clean and helps to reduce the swirls while washing.