Combine baking soda, citric acid, Epsom salt and cornstarch in medium-sized bowl

In a separate small bowl combine oil, water, and vanilla extract and stir well.

Add the liquid ingredients very slowly to the dry ingredients. Mix with hands. 

The mixture should hold together in your hands without crumbling. If not, you can slowly add a few more drops of water until desired consistency.

Firmly pack mixture into the molds you are using. Let dry in molds for 24-48 hours. ***If you want to add sprinkles to the top of your bath bomb, place them at the bottom of your mold before adding mixture.**

When dry, remove from molds and store in airtight containers or package for gift giving.