Mix together the borax, washing soda, kosher salt and baking soda
Slowly add in the vinegar. It may bubble up a bit.
Add in the water, OJ and zest. Using your hands, mix together until it is like wet sand you would use to build sand castles.
Put in molds and pack down. I used an old ice cube tray and some silicone candy molds. I found the silicone was easiest to remove. Allow to dry for a couple hours until hard.
Store in an airtight jar.
Recipe by Saved By Grace at https://savedbygraceblog.com/diy-dish-tabs/