Replying to Dying Full Tilt Tongues?

So I have a pair of full tilt classics from a few years ago and I was wondering if i could dye the tongue which is now red, to black. My plan was to just get some black food coloring and put a bunch of it in a pot of boiling water and it would dye. I'm not sure if it would work right though, would it like warp?, would it not even dye? If anyone has done this or has an insight on this please let me know so I dont fuck up my boots :)
Thanks!