Storing Left-Over Yarn

When you finish a knitting project and have left-over yarn what do you do? There are so many options including letting it languish in the hidden darkness of a blanket box, finding it two years later knotted and mixed up with dozens of other left-over ends of yarn. (yes I admit it, I have knitter's stash shame!) So what to do if you'd like to keep and preserve the odds and ends for future projects... I've a few answers for you here, please let me know in the comments how you store your yarn and return next week when I'll be finishing this tutorial with a Part Two.