Hi guys, so I recently went to take out my choke out of my sb2 and realized that I forgot to clean it at the end of duck season and my choke had rusted and got stuck in my barrel. After a trip to the gunsmith who got it unstuck, there is still a lot of rust built up on the threads of the choke. I tried soaking it in hopps no. 9 for a few minutes and taking a brush to it but it didn't remove much. Does anybody have any other ideas? Also there is a little rust built up on the threads inside of the barrel, I've put a little hopps in there but it hasn't came out. Any ideas there? Thank you everybody I appreciate it!