I take the chain off and put it into a bottle, then use WD-40 as a solvent to cut the existing lube and dirt. Shake well. If it's especially dirty, it might need some scrubbing with a toothbrush. Rinse with water, pour in Simple Green and hot water to get rid of the WD40. Shake well again. Rinse, and dry with towels. Put the chain back on the bike and lube.