Has anyone done this? What I find on the net varies from using leftover grounds to letting sit in sludge for several hours. I am afraid it wouldn't be colorfast. Would you add vinegar to it the way you do with Kool-Aid? I'm talking sock yarn here, BTW, for a caffeine addict who's my best friend.
um well this isent yarn and didnt get washed or anything but....my grandmom was asked to make a black doll (cotton fabric) for her friends daughter and she had a bunch of cream skin fabric so she took the doll body (already sewn but not stuffed) and left it outside in a pan with lots of tea bags (and water) the doll turned out great but like i said i cant tell you how well it aged...
I've dyed mordanted superwash wool with coffee (boiled for awhile then the yarn was kept hot in the dye for one hour) and the color was dark and rich and so far lightfast but it hasn't been washed (in an afghan). It was difficult to wash the coffee grounds and smell out. I put it through the washing machine twice after leaving it out in the rain for a couple of rainy days - those days aren't hard to find in Oregon.
I like to have my yarn rinsed by the rain as it leaves it so soft.