You've probably had to erase stuff before. Blowing away eraser shavings is hard work though, and if you just brush them off your paper, your drawing our writing or whatever it is could get smudged. This is the Instructable you've been waiting for all your life.
Step 1: Materials
Foam, paper, scissors, glue, pencil(optional).
Step 2: The Cuttening
First you need to cut a rectangle out of the foam and a larger rectangle out of your paper.
Step 3: The Step With a Less Cool Name
Fold your foam in half and glue to the paper. Let half of your foam stick out.
Step 4: Finishing Up
Roll up the paper and glue together and cut the foam so it has little foam bristle thingies. If you want, you can stuff extra foam in the middle of the rolled up paper so it's less flimsy.
Step 5: Test It Out
Now sweep things!