Okay. This may be too rough for you, but I like murdering sweaters. Especially evil sweaters that are trapping beautiful yarn in an ugly shape or pattern.
For example, I found one terrifying 80’s sweater — cropped, mock turtleneck, hideous stitch pattern — at a Goodwill near my house, and it was holding hostage a ton of absolutely gorgeous white 8-ply baby alpaca yarn. Sweater? Hideous. Yarn? Gorgeous.
This may be obvious, but you can get a full sweater’s worth of yarn for the cost of one Goodwill sweater (or for free, if you already own the sweater).