SWAROVSKI ELEMENTS flatbacks are here! Please note that when using flatbacks, you should never use a glue gun or super glue (cyanoacrylate) as they will damage the foil backing on the rhinestones. Also be aware that while flatbacks are terrific for adding sparkle to clothing they should never be dry cleaned. Take a look at the various flatback and hotfix sizes, and see how they relate to the size of a penny!