Cells from the inside lining of your cheek are good for learning how to stain.

Make a wet mount but use a drop of methylene blue stain instead of water.

Gently scrape the inside of your mouth with the flat side of a toothpick. This scraping will collect some of your cheek cells. (Don't worry; these cells are constantly being shed from your mouth so they will not be missed!)

 Place the cells on the drop of stain by scraping the used side of the toothpick against the drop of stain.