.357 mag,
Traditional oils and solvents won't harm the bluing on your revolver. Hoppe's, Outers, Rig, etc. are all fine products that won't damage the blue finish. Just
never use one of those
Lead-Away treated cloths on your blued gun unless you want to remove most of the bluing.
Care:
- Invest in a soft cloth for wiping down your gun. Gun shops sell plain, oil-treated and silicone treated cloths. I prefer plain and I can use my own oil. Even better are old baby diapers - they're cheap and last forever.
- After cleaning and/or handling, apply a drop of oil to each side of the frame and spread with the cloth to cover the entire gun. I've never used more than about 6 drops of oil and this suffices to keep rust away.
- An alternative is to use a good carnuba wax to put a barrier between the metal and the air (moisture). You can use something like Flitz Rifle/Gun wax (very good product) or less expensive Johnson's paste wax (less expensive). Use rubbing alcohol to remove all external oils or grease, then apply with a clean, soft cloth. Let dry and buff off.
- If you live or store guns in an area that gets humid, store them with a VCI product to reduce the chance of rust forming. This is in addition to using oil or wax on the gun.
- Standard bronze bristle brushes won't damage the bluing right away, but don't use excessive pressure when you can avoid it. Always use some lubrication with a metal brush (solvent or oil).
Brake cleaner doesn't affect bluing either and can be used as a degreaser. Nor does WD-40 damage bluing, though it makes a poor lubricant and rust preventative.