1/3 bar Fels Naptha, grated. You can also use Ivory bar soap, you will need to use the entire bar.
1/2 cup Washing Soda (Arm & Hammer)
1/2 cup Borax Power (20 Mule Team)
You will also need a bucket with a lid that snaps. I bought one of Home Depot’s 5 gallon orange buckets.
Grate the bar soap and put it in a sauce pan. Add 6 cups of water and heat until the soap melts. Add the washing soda & borax and stir until it is dissolved. Remove from heat. Pour 4 cups hot water into the bucket. Add your soap mixture and stir. Now add 1 gallon + 6 cups of water and stir. Let the soap sit (covered) for about 24 hours and it will gel. You will use 1/2 cup per load. Be sure to keep it sealed.
This recipe easily doubles and fill the 5 gallon orange bucket.
I also use white vinegar in a Downy ball.