Lighter the colour, the less abrasive, the darker, the more aggressive.
Black is ideal for super heavy duty scrubbing and removing heavy wax build up. Green is used for heavy duty scrubbing and removing tough built-up grime. Brown for light duty scrubbing. Removes light wax build up. Blue is for medium duty scrubbing. Red is ideal for light duty scrubbing. White is non-abrasive for high gloss finish.