Those CD's you get in the mail I simply use as is with the shiny side up for coasters.
Empty peanut butter jars make great storage containers for alot of things. I clean mine out lst with papertowels, then wash in hot soapy water and dry. After clean and dry I use them to store noodles, dry beans, candy, and basicly any bag form of grocery product that will fit inside. I sit them on my kitchen shelf unit for display and it keeps critters out. You might store them in your pantry.
Also I use them for my son's and grandsons' little toys...bugs, micro-machine cars, small plastic dinosaurs, or odds and ends.