Acrylic won't dye very well.....at least I don't know of a dye that will work well on it.
I have dyed wool yarn with Rit....but that wasn't very successful at all....
Linda C

for dying at home you really want to use natural fibers such as silk, linen, cotton, wool or rayon. Dharma trading has wonderful dyes that don't require professional equipment. They are wonderfully vibrant. I personally use Procion Fiber Reactive dyes.

Here is a link that might be useful: {{gwi:1480357}}