I'd look into what's in your "Lemon oil with beeswax" I wouldn't use it if it has natural lemon oil or other acids.

This brings to mind a little Irish pub I frequent. They have tables covered in copper sheet. The tables get tarnished of course. One night a fine lass joined me and a friend for dinner at this pub. She started playing with the condiments on the tarnish and found a little ketchup or mustard cuts the tanish immediately. I can only imagine what it might do to a blued barrel.