Just ask the flanneled-out guy in army boots over there: grunge and brushes just don't mix. Exploit that adversarial relationship with the Finish Line Grunge Brush Chain & Gear Cleaning Tool, the most grime-zappingest crudsweeper on the block. On one end it has horseshoe bristles that surround your bike's chain on all sides--like government agents taking down a grime boss. The other side has longer bristles that are made to floss between cassette teeth, derailleurs, and pedals. Just remember: cleaner is faster.