In a large bowl stir together baking soda and citric acid until well combined.
Add oils and stir to mix thoroughly.
Place vinegar in spray bottle and spritz baking soda mixture lightly. You do not want to soak it or you will cause the fizzing reaction and it will not be effective for cleaning. Spritz and stir, then repeat. Continue doing this until it is just barely misted enough so that it sticks together when squeezed but not dripping (this is super easy but don't overspray).
Press mixture firmly into the muffin tin. I used these silicone molds because it makes it so much easier to pop out.
Allow to dry. It usually only takes a few hours since it is barely wet. Pop from mold and store in a quart mason jar.