It can be used for many things. I use mine as a to do list and to list bills I have to still pay.
Step 1: Test Plastic Containers
I found the clear containers you get at the grocery store work well.
Find a container that works.
Step 2: Cut and Straighten Plastic
Roll the plastic tightly in the opposite direction it wants to curve to straighten it. Do this a few time until the plastic strip lies almost flat on a table.
Step 3: Stick on Fridge and Use
Then write some stuff and easily erase and write some more stuff.
I wrote work on mine and easily erased it using one swipe of my finger.