Using the box grater, grate the soap bar into a large bowl.
Add the washing soda, baking soda, and salt to the bowl with the grated soap. Mix well with a spoon.
Begin adding the white vinegar to the dry ingredients a little bit at a time, stirring constantly. You’ll notice some fizzing as the vinegar reacts to the baking soda, but adding a small amount at a time will help keep this minimal.
Continue adding vinegar until the mixture is clumpy and holds its shape when pressed together. It should feel slightly damp and just hold together when pressed between your hands.
Add a few drops of your favorite essential oils if you want scented pods. I like to use lemon or lavender.
Firmly press the mixture into the silicone molds. You want to pack them tightly to ensure they hold their shape.
Set the pods in a cool, dry place and leave them to dry completely. This usually takes about 24 hours.
Once they are completely dry, pop the tablets out of the molds. Store them in an airtight container out of direct sunlight.
Notes
I’ve included step-by-step images in the post above for visual guidance. If you would rather watch, I’ve included the complete step-by-step video tutorial here in the recipe card!Keep these out of reach of children and label them well!To use a laundry soap pod, toss one into the washer drum before loading the washer with clothes. Pods are suitable for standard and HE washing machines.Be patient with drying time. If the tablets are not completely dry, they will crumble when you try to remove them from the silicone mold. Check out the above post for troubleshooting tips. You can use a fels naptha soap bar in place of the castile soap.