I've been wanting to try this for the longest time... So, finally, I went to l'Armée du Salut and bought three shirts for about 18 $. Two of them (100% wool) will be for dyeing, the other (a mix) will make nice socks or slippers. Really, a Gap 100% wool shirt for 8,50? They are presently in the wash with Woollite, partly because I don't trust their cleanliness, partly to get rid of the smell.
I really wanted to try dyeing with Kool-Aid, but it's proving nearly impossible to find in Montreal - the traditional, unsweetened kind, at least. I'll see if I can find some in the U.S. in March.
In the meantime, I'll dye with vinegar and food colouring, which does exactly the same thing, without the fruity smell. But Kool-Aid has such nice, vivid colours!
I promise pictures :-)