REUSING MATERIAL FOR THE CLASSROOM

How are you reusing material in your classroom?
In my classroom there are centers that I have created from material that can be reused over and over again.  For example, the tops of water bottles are used to write letters, numbers, words, etc.  I also use them for a match game where I cut out pictures and glue them onto the tops.  Old magnetic flyers or advertisements are perfect in your magnetic center (for obvious reasons).  You can glue them onto the back of pictures, flashcards, instructions etc. Shoe boxes are great to store material, student work and my favorite...sand.  The sand is poured inside of the box and students can practice writing words, numbers etc.    If you have creative ways to REUSE material in your classroom, please share.