Originally Posted by timcupery
Before installing the chain, put it into a soda-bottle with mineral spirits (paint thinner) or simple green (a water-soluable, biodegradable degreaser) or whatever, shake it up a few times, let it sit overnight. You should get this gunk out. Then rinse the chain, wipe off any residue, and install it and lube with ProLink or whatever you use.
+1, By now, Cheeseflavor, you've got more recommendations than you ever wanted. I agree with timcupery, but I use simple green for one reason. Kerosene or mineral spirits will strip all the lube off. When I've used these degreasers with a NEW shimano chain, tiny rust spots occurred after rinsing with water to remove the degreasers. When I use Simple Green and the soda-bottle to shake like tim said, it leaves a very thin layer of the factory lube that resists oxidation, resulting in no rust after rinsing to remove the degreaser.