Crisco is for Cooking, lets leave it at that. Boiling Water is Bad, like Semisane said it causes Flash Rust. I used to use Hot Water and Soap to clean the Bore, but befor I could get a patch through it, it was already Rusting! So since then I just use warm or cold water. Also I suspect the barrel was'nt completely dry and the Crisco mixed with the water and there's your rust. To protect your investment get a good quality Gun Oil, Montana X-Treme Gun Oil, Casey Sheath Barricade, Montana X-Treme Bore Conditioner. Make sure your Bore is completely dry then apply one of the oils mentioned and there's no way it will rust.
Give your ML a good rubbing with JB's, that should get it off. Remember, DRY, then Oil and you'll be fine.
Good Luck!
(BP)