When I started back to knitting, I found a large attractive basket to store my stash. It's looks lovely, all the different colors and textures heaped up together. "Isn't this just lovely," I say to myself with gritted teeth while I'm digging through trying to figure out what's what.
Then, I started clipping a 4" to 12" sample of yarn (depending on the color pattern) when I first get a new skein. I staple that sample to the band that came on the skein, and the band to a note card. In lieu of a band, I write the particulars directly on the card. My goal is to set up a card file organized by 1)weight, 2) type, i.e., wool, cotton, acrylic, etc., 3) color. Or maybe by type first, then weight. I'm not sure what's best.
So, I can now have piles of pretty balls of yarn and still know what it is. Also, I can write on the cards what was made with the yarn so I can track care instructions. And, perhaps the file should be in two parts, one for yarn still in stock, and one for yarn that's been all used up but for which I still want history and care instructions.
Right now, of course, I have a big pile of bands with yarn stapled to them