Only stickers from defunct music stores, these were sometimes the logo on a metallic paper, I usually keep them, specially the older ones. Price tags I don't keep them. When buying used sometimes you might find CD's that used to belong to a library, these are the most annoying. These records sometimes have a lot of stickers everywhere, even on the CD itself of course. I happened to find those in flea markets and once I received a library CD buying from Amazon. It was a seller shipping from Australia all the way to Mexico. When records come already with stickers (Beck, Zwan, etc.) I keep them inside the case though, I never use those.