1. Combine corn starch and baking soda; sift until well combined.
2. Add coconut oil in a liquid state. Stir it all until it forms a lotion/cream.
3. Apply to armpits as needed.
Depending on room temperature or how you like your deodorant, you can keep it in the fridge for a less convenient but more solid deodorant or leave it someplace warm for a more creamy deodorant. The coconut oil is supposed to be non-staining, but experiment on your own items. I used to use baking soda and witch hazel and make a roll-on with it, but with the addition of corn-starch the deodorizing and antiperspirant factor was significantly bumped up! Try it for yourself!
Source of recipe: I stumbled upon a similar recipe online and tweaked it a bit.