I've not had a chain driven bike in many years but this is what I used to do. Remove the chain from the bike and place it in a film can or other semi shallow metal container coiled up. Add 10W30 or 10w40 to the container until it covers the chain and place on a Colman stove then boil the crap out of it. Ten or fifteen minutes should be fine or until you feel the chain is clean, let the oil cool and remove the chain from the oil wiping off excess oil as you go. It's best to let the chain hang for a day to let any residual oil drip out, re-wipe, reinstall and ta da nice shinny clean and very well lubricated chain. Hope this helps.