[63 & 64 Bowties]

I know this sounds crazy, and it's not EPA approved. But, I did it years ago on a homemade flatbed on an old International I had.
Dissolve asphalt patch in kerosene to the desired color then paint it on. When it's done, you can spill used motor oil on it and you won't see it. Of course you have to let it completely dry out and cure before you mount it cause it's gonna be pretty flammable when wet. Kinda gives the wood that old telephone pole creosote look.