These little bottles are great for altered art, soldering, or firing on metal clay attachments and more! See Tools: Glass Soldering for supplies and the great book, Books: Simply Soldered Jewelry and Accessories. This way you can put all sorts of found objects in the jar and instead of using the lid, solder on a bail or jump ring. Or use them with metal clay, but make sure the contents can be fired!
They also make great containers for pixie dust, glitter, gold, stones, oil paste and more!