It will remove the painted finish over time. It is a good solution for the internals and trigger pack. Re-lubing after cleaning to protect it from corrosion and for lubrication would be needed. Simple Green Extreme is usable as an envirosafe solvent in ultrasonics. Ultrasonics clean hardened deposits better than softer deposits. Put the dirtiest parts in a ziplock bag with solution to keep the solution in the tank cleaner longer. The ultrasonic vibrations will clean through the bag.