An idea for those with so much yarn you couldn't ever get through it all ... Set a date once a year to go through it all and decide what you could, actually, part with. Then bundle it all up, and bring it to a nearby nursing home, with any spare needles or crochet hooks you might have lying around.

Homeless shelters sometimes will also accept this, or places that work with abused or battered women, as it gives women something constructive they can do with their own two hands, and in the case of nursing homes, helps pass the time. Many elderly women learned to knit or crochet as girls, and it gives them something nice to do. One lady at our church spent time every year with any yarn she could get knitting mittens, and we'd present them - along with others' contributions - every year at the beginning of winter to a group in Boston that worked with needy children.