I thought break cleaner, and wd 40 worked until something broke.
I’ve used both on firearms for various tasks.
When I was heavy into Cowboy Action Shooting, I used a pair of Colt Single Action Army .45’s. I would be shooting all day, in the Georgia sun, and handling those Colts with my sweaty hands. I would come home and all I wanted to do was relax. I would pull the cylinders out of my Colt’s, and spray all the metal, inside and out, thoroughly with WD-40. They would set that way for 1-3 days. They never rusted and were very easy to clean at that point.