Re-dye Carpet.

I have read numerous threads relating to older black carpets changing to a blue color. I've seen pictures of this and my 308 has the same problem. Does any one know what the carpet is made out of and is there any products out there that you can use to re-dye the carpet back to black? I once dyed my 63 Split Window's carpet black with Ritz Dye and it work OK except when ever I worked under the dash on my back my T-shirt would turn black. I would like to use something that can be stablized and I would prefer to dye it in the car. Any ideas?
Charlie