It might come out crap, but it could totally come out GREAT! I had these big chunks of quilt batting stuff which was actually superwash merino (i loved that order, but she can’t get any more! /pout) that I’d dyed and wanted rainbow, but I’d somehow bunged up the red cake dye to water ratio, or something, and it came out this really sickly colour of pink. And pink IS my favourite colour, so if I look at it and it turns my stomach, it’s definitely a bad, bad shade. So I hung onto it for a while, and then remembered that black cake dye is extremely unstable, doesn’t dye totally black, ever, and tends to separate into the composite colours at random places in whatever it is you’re trying to dye. So I went ahead and over dyed the whole bunch o batts with the sickly pink and otherwise okay rainbow colours, and let me tell you, it came out ossum. Ossum like Possums. It’s still to this day probably my most favouritest result from a “let’s see what I do when….”. Now, I don’t know that over dying with black cake dye would rock that world o fisherman’s yarn, but perhaps some cake dye, when you locate it, would be in order. You never know. Or just full yourself something so obnoxiously bright it’ll be bound to be a carrying pouch for Mazie’s favourite dolly or Sesame Street stuffed pal

You could try overdyeing the whole thing with a very weak purple bath and see what happens …