Powerwash that off to get them to get a light layer of rust if you dye/wax them. I use the heated dye and waxing as it gives them a nice color and the wax seals the trap, speeds the trap and prevents minor freeze downs.
I never could get that dipping a trap into gas or tar and feeling good about it, many do but not me!
Born in the Big City will die in the Country OK with that!!!