A dirty bicycle chain will wear out much faster than a clean one, which is why it is important to use a chain degreaser regularly. A chain degreaser removes grit and grime that can work into the rollers and plates of the chain. The more grit and grime present on the chain, the more likely the chain and gears are to wear out and slip. A good chain degreaser will remove most of the dirt on the chain quickly and thoroughly, and a citrus degreaser is a good choice for doing so. Some chain lubes also remove grit and grime upon application, and the chain will be properly lubed after cleaning.
Citrus chain degreaser products use orange peel extracts, which are effective in breaking down components that can damage your chain. Periodically leaning a chain with such a degreaser is a good idea, and is best done with a chain scrubbing machine. The chain runs through the machine, which features durable bristle rollers, to clean the outside plates of the chain as well as the rollers in between the plates. Once the chain is clean, it should be dried with a rag, then lubricated with a proper chain lubrication.
Some chain lubes naturally act as a chain degreaser. Thinner, oil-based lubes — as opposed to wax-based lubes — can penetrate into the rollers, pins, and plates, to wash grit and dirt away. When lubing your chain, you should apply a generous amount of lubricant all the way around the chain, then use a clean rag to wipe away the excess. The dirt and grime will come off the chain along with the excess chain lubricant. It may be necessary to re-lubricate the chain after an initial application, especially if the chain is excessively dirty. Otherwise, lubricant should be applied to the chain before every ride, or before every second ride, if the lubricant is oil-based.
Wax-based lubricants do not act as a chain degreaser. While chains treated with such lubricants will not need to be re-lubricated as often, they will need to be cleaned more often. Wax lubricant can build up between links, pins, and plates, and a citrus degreaser will be necessary to break down the wax and remove it. Most degreasers available today are citrus-based, and choosing the best one will come down to preference, price, and environmental concerns. Look for a lubricant that is biodegradable and does not contain harsh chemicals that can hurt the body or the environment.