1 bar (5.5 oz) Fels-Naptha soap, finely grated
1 cup washing soda -- I used Arm & Hammer Super Washing Soda
1 cup borax
1/2 cup OxyClean
12 drops essential oil (lavender in my case)
Use 2 tablespoons per load. Pour it in while the water is running to allow it to dissolve. I use cold water and have no problems!
Basically, you just mix all this together in a big bowl! That's all there is to it. I figured out that it's so much cheaper than buying detergent and it works great. I found everything I needed at Kroger. Wal-Mart didn't have the stuff, so if you decide to try it out for yourself, you might want to call ahead to make sure your store carries everything. Also, you don't have to use the essential oil, I just have it on hand from making the rest of my cleaning supplies. This recipe will make enough detergent for about 18 loads of laundry. Since I was just testing it, I made only one batch, but next time I'll do 2-3 at once.
I also decided to try vinegar as a fabric softener, because that's much cheaper as well. I bought a small jug of regular white vinegar and added about 15 drops of essential oil (again, not necessary). All you do is pour 1/2 cup of vinegar into a "Downy Ball" ($1.50 or so in the fabric softener aisle), seal it, and toss the ball into the washer on top of the clothes. Just don't put the ball in the dryer along with the clothes! :)
I used the same essential oil scent in both products, but you could use complementary ones, too -- I will next time! And of course, you can adjust the amounts. My laundry comes out with a light, fresh scent with just a hint of lavender. It's not strong at all.