I've tried various methods. Mineral spirits work pretty well. A variation on this is to put the chain into a large mouth bottle (like Gatorade) with a solvent (mineral spirits, Simple Green, Tide, etc) along with cut up pieces of a Scotch Brite pad. Close & shake. Let sit. Repeat. The Scotch Brite pads do a good job of scrubbing the old lube & dirt off.