Natural Dishwashing Cubes

1 cup borax
1 cup washing soda
1/3 cup Epsom salt
Lemon Juice

Mix all powders together in a large stainless steel bowl
In a smaller bowl, take one cup of the blended powders and add 4 Tablespoons of the lemon juice. When you add the lemon juice, the mixture will foam when it hits the powder- mix it until its sticky.
Spoon the sticky mix into an ice cube tray and pack it into the ice cell.  When you run out the mix, just mix up another cup.  Mix it a cup at a time until you use up all the powder.
Place the tray in a sunny location to dry for a couple of days.  In dryer climates, like here in Colorado, it'll dry a lot faster.
Once the cubes are fully dry, just tap them out of the ice cube tray. 
You can store the dry cubes in a Tupperware or glass container. If you live in a humid environment, add a little rice to the bottom of the container to absorb any moisture, or you can include on of those little silica gel packs.