How to set the colors when you've already knit the sweater!

I didn’t set the colors in a sweater I just finished because the skeins were already in balls when I got them. Does anyone have a fool-proof way to do this. Surprisingly, it is difficult to get an answer via Google. Thank you for any and all ideas!

What do you mean ‘set the colors’? Most yarns won’t bleed, which one have you used?

I used cotton classic elite and they have run all over the place in the past. I thought they were colorfast, but was wrong. I just don’t want to take any chances this time.

I think putting vinegar in the water works. You might ask in the Spinning and Dying forum. Or search using ‘setting the dye’ instead of setting the color.

I’ll try there with the edits. Thank you!