Cosmoline in an oil can.

[BigD7]

So I've been cleaning my new Mosin Nagant 91/30 (Christmas present) for the past few days. It has a lot less cosmoline on and in the rifle than I thought it would. I still have more cleaning to do though. But the oil can that came with it was coated in cosmoline. When I opened it up, there was cosmoline all over the inside. The outside was easy to just wipe off, but I don't know how to clean the inside. Should I just pour hot water in it and swish it around for a while?
The bayonet is also a pain to put on. I can get it on up until right before I have to rotate it to lock around the front sight. It won't slide off without the help of a couple light taps from a hammer. Any advice?

[DefensiveCarry.com]

[frankmako]

brake cleaner should take it out.