Add 1 cup of washing soda (about 300g) to a large glass bowl.
Add 1 cup of citric acid (about 250g) to the bowl.
Add ½ cup of salt (about 140g).
Add your Essential Oils if using. I added 10 drops of Lemon Essential Oil and 10 drops of Lime Essential Oil.
Place some distilled water in a small spray bottle and spray the mixture lightly before stirring. You need to add the water slowly as you don't want the mixture to start fizzing too much.
Keep spraying and stirring until the mixture just starts to clump together in your hands.
Press the mixture into your moulds, silicon work best.
Let the mixture dry for about 24 hours before popping out.
Place in an airtight container.
Use one tablet per load.