Place borax, washing soda, essential oils, and soap in a spray bottle (preferably glass).
Add distilled water until the bottle is almost full. Be sure to leave room for the sprayer. Distilled water is best, but any water that has been boiled will work.
Screw on the lid and shake well. Use as needed. I use it as a bathroom cleaner, floor pre-treater, kitchen cleaner, and on toys.
Notes
Store your cleaner away from direct light and heat. It should last for about 3 months when stored properly.