A few years ago, a buddy gave me the carton of every blue moon style of beer and thought they would look good up on the wall. What a great idea indeed! Since then, I've been saving every one to eventually frame and run across the top of the bar. I probably have around 200 already and some of my favorites are pictured above.
After looking online at a few of the dollar store sites, there are definitely some viable options for frames. You could also paste them to a poster board to put up in your garage or brewshed. All you need is a nice pair of sissors or paper cutter to get started.
Most containers will rip right in half by pulling the sides apart (up by the handle). Once it's split, put one of the sides face down on a flat surface and rip out the supports. Being double-sided, you will have two chances at this if it tears--or if it was already wrinkled or bent by the time you got it. Finally, cut off the excess on all sides.
Now if I could only get them signed by the brewmasters!