If you wish to be crazy like me, you will need the following:
Okay. Now...be bold. DYE.
Please, oh please rinse it out thoroughly once you've dyed it for the appropriate amount of time. Set aside in the bowl, and then run it through the washing machine with soap.
My old sweater was hot pink, so combined with the black dye it produced a lovely shade of purple. Yays!
And done. Wasn't that easy??