Not a gunsmith but looks like the parts were not hot enough to evaporate all the water and some spots were left that rusted. I would try some flitz metal polish and see if it does any good. Anything much more abrasive like steel wool will start to take the finish off although some get away with 0000 steel wool. You might try soaking with a penetrating oil like Kroil or transmission fluid for a day or two and then try.

"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli