I'm in a cleaning mood, which is good and needed because I have very little room for stuff and things need to be sorted, put away or disposed of. Yesterday I went through three years' worth of receipts (2000-2002) I'd saved, manually shredding all of them, and doing so especially thoroughly when credit card info and signatures were on them. And I threw away the pieces in different trash receptacles, including among intentionally wet trash.
Receipts actually break down in interesting ways: many of them feel rougher after a few years, and more strikingly, some of them become sparkly, and the sparkles can fall off the paper and onto you. And many of them were rubbed into unreadable-ness. (Which once inspired me to write this.)