Muc-Off Drivetrain Cleaner: 500ml Pourable/Spray Bottle. The Muc-Off Bio Drivetrain Cleaner is a complete drivetrain cleaning solution that can either be poured into a chain cleaning device or sprayed directly to your chain rings rear cassettes and derailleurs to clean your entire drivetrain within seconds. Its also fully biodegradable and safe for metal plastic rubber and seals.