How do you remove hair dye that's on a rubber bath mat?

I purchased a rubber bath mat. My daughter dyed her hair and the mat became stained. I have washed it in in the washing machine and there was some improvement but the stains have not been completely removed. Is there anything else I can do? I do not want to try chlorine bleach for fear of ruining the mat.

I used shout, spray and wash, and stain devils chocolate and coffee stain remover. I left them on for about 10 -15 minutes, then let them soak in our front-loading washer (less water) all night. In the morning, it washed and the stain is nearly non-noticeable, but not completely gone... am still searching. I know of the product "blue magic" which removes old carpet stains, but I'm a little hesitant to use it as it might eat away at the rubber bottom. I'll let you know if I discover anything else.