Reusing requires a little creativity. By nature, kids are some of the most creative creatures on the planet so get those innovative juices flowing and watch what happens. Either provides some of your own items or have the kids bring in things from home. You want a wide variety of things that could easily end up in the garbage, such as empty food containers, dried-up markers, broken toys, torn of stained clothing, packaging, and wrappers. Everything should be thoroughly cleaned, and nothing with sharp or pointy edges should be used.
Divide the students into several groups and give them each a pile of random junk to work with. What can they make? All of the items can be used to make one new item or several different items. The children should work together to reinvent a use of the junk. Set their imagination free by allowing them to invent things that have never been seen before.
If your school has a display case, ask if your class can exhibit its projects there for a while. Post a sign asking if people can identify what materials went into each piece. Kids for Saving Earth provided many ideas for turning trash into an eco-carnival. You can even earn money through creative thinking with trash. Put your kids to work thinking of games they can make with trash.