Probably get down voted for not being safe, but when I used to dye my hair and inevitably dye my skin, I'd pour straight bleach on my hands. I mean, it'd be in a sink with running water and soap next to me so I could immediately wash the bleach off, but it always worked for me. Of course, I works so this right after I was done dying so it didn't have time to set in

I was also told once by a hairdresser that cigarette ash works to remove dye