In a large bowl, stir together baking soda and citric acid until well combined.

Add the essential oils and stir to mix thoroughly. I recommend using a metal whisk as it does a great job of breaking apart the drops of oil throughout the mixture.

Place vinegar in spray bottle and spritz baking soda mixture lightly. You will see a small fizzing action, but it will quickly stop. You do not want to soak it or you will cause the fizzing reaction (baking soda + vinegar reaction) to occur too much and it won’t 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.  You want it to be moldable like wet sand – but just barely wet!

Take a handful of the mixture and firmly press it into each of the 12 silicone molds. You may see them “grow” a bit from the vinegar + baking soda reaction as it dries.

Push them firmly into the mold to keep their shape. It will take a couple of hours for your toilet cleaner fizzies to fully dry. Let them sit over night before popping them out of the molds.  

Pop them out of the molds and store them in a mason jar or similar container.