These are truly only temporary bottle cap decorations! I'm going to place them around the art show to add to the foodie yum yum theme!! :) ha ha I'll pop the caps off the painted cardboard after the show and reuse them. They are attached with only Elmer's..which I would never recommend because they do not stay attached! Elmer's dries very hard/dry/brittle....so the POP off if you bump or bend the board. This is fine for what I'm using them for..and will make reclaiming them extremely easy! If I wanted them to stick a bit better to the cardboard...I would have had the students use tacky/craft glue. It tries with a more plasticy/rubbery texture..which gives a bit when the board is bumped or bent. I gotta tell ya....my 1st graders had SOOOOOOO much fun doing these. Next year when we redo the outdoor bottle cap mural...I'll be sure to include the younger grades in on the fun!