Grind up the oats with a mortar and pestle. You can also get pre-ground oats, like the Aveeno package shown, or leave the oats as they are for a more rough facial.
Add about 1/2 - 1 tsp baking soda for every 1/2 cup oats. Add a heaping tbsp cocoa and mix.
Add one or two more spoons cocoa until the aroma is to your liking.
Spoon the powder into a container or ziplock bag and store in a dry place until ready for use.
Mix around 2-3 parts water for every one part powder if you want to wash your face. For a mud mask, use equal parts water and powder.