I think the stuff in the US is called "rit" dye.. You can probably buy it at Walmart or whatever(I hate Walmart though, so buy it elsewhere.. )

Anyway, get a big pot, fill it 2/3 with water(enough so two rims will be submerged..), add a tabelspoon or so of salt, bring it to a simmer, so it's just under a boil, mix in the dye(it's crystals..), and ease in your two rims. I did a search on another forum and the guy said do 2 rims 5 minutes at a time, but that wasn't enough, so I left two rims in for 15-20 minutes.. The time is only important I think if you want to dye colors like orange or green or whatever.. For black I just leave 'em in for a good 15-20 minutes.. Then - being very careful to not get black dye all over your kitchen - take the two rims out and immediately rinse them with cold water in the sink.. It won't stain your sink BTW - but it may well dye your counter, floor, clothes, etc.. But if you're careful it's no biggy..

So, pot, 2/3 full, add salt, bring to simmer, add dye, add rims, 15-20 minutes, take out and rinse under cold water, done.

I just threw the wing in and left it for 15 minutes...

It's really totally easy - at least if you're only doing black....