Outside of starting with an FDE stock and going to foliage, I can't say there's many other ways. I don't think even bleach will take it to the color you want, though I could be wrong.

Could always just have one cerakoted. Should be pretty inexpensive to have just a single stock done.

I've done a lot of hydrographics/dipping as well. I don't offer it now because I felt the actual cerakote was nicer. However a dip with a clear coat of Cerakote is reasonably strong. I just didn't like the colors or some patterns offered. People want custom and you're limited to just the films available.

That said, Cerakote is very tough. Will it last forever? No. If you purposely abuse it and drag it around, it'll wear. If you stab it with something sharp, it might potentially scrape. BUT when properly done, it'll easily last and show great abrasion resistance and toughness. It won't peel and it won't chip. It will only wear in spots where there's potentially consistent rubbing or a sharp edge brought to it. In those cases it won't remove material in any places that were not directly involved.

I think it's your best option unless you just want to hit it with some rustoleum or something. But that will certainly wear differently, in a way you don't want.