?Cleaning the chain and gears has never been so quick and easy. The Grunge Brush is a heavy-duty cleaning tool that can be used wet or dry. Use the horseshoe tip to scrub the chain and the shaggy tip to clean sprockets, pedals and derailleurs. The brush blocks can be removed for cleaning or replacement. The Grunge Brush is called the “Portable Chain Cleaner” and as such, cyclists often bring it with them when riding in wet and muddy conditions.