Clear soda can.
https://s3-us-west-1.amazonaws.com/h...n_fullsize.jpg
Previously:
https://www.homemadetools.net/forum/...867#post202454
https://www.homemadetools.net/forum/...635#post151794
https://www.homemadetools.net/forum/...219#post161318
https://www.homemadetools.net/forum/...179#post115843
https://www.homemadetools.net/forum/...515#post139353