Can't wait to try the vinegar "treatment." Although, it does sound rather harsh. That's very acid. I have a brown stain on a crocheted child's cape (from the 70s) that formed after being in a cedar chest for some time. It wasn't wrapped, but it was away from the sides of the chest. I usually use Biz and Ivory Snow to soak out stains. Usually works very well (haven't tried it on the crocheted item).