It depends on how patient you are.

The best and simplest is 50/50 ATF & Acetone in a sealed container that is agitated! Like setting the container on top of, or in a case polishing tumbler if you have one. Plan at least a week before checking the progress. It will remove rust down to bright metal w/o harming the remaining bluing when done correctly as I suggested above.

Any of the laborious physical methods will not help the innards if you don't want to remove the side plate and disassemble the action parts.

__________________
Jim
S&WCA #819