I made a soap last year that I'm in love with. We use it for laundry, house cleaning, dishes, and tough messes. It cuts grease with no waters or cold
water. I made it out of necessity when we had no
hot water last summer and 'eco friendly' dish soap couldn't hope to contend with our greasy dishes.
I've made it into bars, which are nice for cleaning very gross farm hands, and it's also decent at dish work, just rubbing the bar into a lightly wetted greasy pan and it's like a grease eraser. Mostly though I make big 5 gallon
bucket fulls of it in liquid form. It can be as thick as guacamole or as thin as kefir. It's super satisfying when it's thick, but I try to run it on the kefir side because it's so strong and, really, a little goes a long way. So having it super runny helps stretch it farther when we over-use it.
The recipe is lard (or other oils), water, lye, and borax. That's it. The borax is the detergent agent there. The soft/liquid soap is also insanely easy to make. The first time I ever made it I did this recipe:
7.5lbs oil
1.1lbs lye
8cups borax
4.5~gallons water
(I also like to add about 20 drops of eucalyptus and 20 drops of lavender EOs, it leaves a very subtle scent that's simply 'fresh')
Put 3 gallons of water in your 5 gallon bucket and slowly add lye, stirring and incorporating it. Monitor temp with metal meat thermometer, meanwhile heat oil up gently on stove. When the lye water cools to about 120º and the oil heats up to about 120º, gently and slowly mix the oil into the lye water. Once oil is added and the mix begins to trace (firm up and leave streaks from stirring) add the borax and stir fitfully. Add fragrances at same time as borax. Add more water until the bucket is close to full. Once the borax is in I generally just keep the bucket nearby and stir it as frequently as I think about it, every hour or so maybe. It might take 2-3 days, but the liquidy soap will turn into yogurt.
We now use a paint mixer with a drill to quickly mix and incorporate our setting soap bucket, since it's hard to really mix it fully with a stick or whisk in that volume. Once it turns into yogurt, even if it's still 'hot' and hasn't settled, it can be used promptly on dishes and greasy messes.
This recipe is pretty powerful. It doesn't bug my skin at all, but some folks I've given it to have said it makes their skin tingle or is generally harsh on their skin. The ingredients could be toned down quite a bit to reduce its intensity. But like I said, we made this to cut grease in ice cold water and wash grimy farm clothing in cold water. Less borax would help tone it down if desired.
You can store the bucket with a lid on it. I like to keep a 1 gallon bucket full for laundry and dish use and keep the rest in a big bucket. If the bucket(s) are left open you'll need to add a bit of water now and again as it evaporates and thickens. We use this soap for virtually everything and 5 gallons lasts us about 6 months.
We've observed no adverse affects using it in our laundry on a wide assortment of garments, blankets, etc. It keeps sponges alive FOREVER. It strips blood out of fabric (as long as the blood hasn't been 'set' with
hot water yet). We run the dish water into a
compost heap and the worms in there don't complain one bit. It has not yet adversely affected our compost soil. The only thing you want to avoid (maybe besides getting it in your eyes or open wounds) is leaving a blob sitting out to dry. It will crust and leave a white residue you have to scrub off. We use about 1/4 cup of runny soap in out miniature washing machine. And honestly we could probably go with half that and be fine.
The bar version of this was very similar in recipe, but must be made more "properly" like finicky bar soaps do, and had way less water in it. The bar version was a soft bar, but I think I used olive oil in mine because I actually wanted a softer bar that I could smoosh into a greasy plate a little bit. Versus a pure lard bar that sets up super hard and resists melting with water. The liquid soap is REALLY satisfying to me. Pure white and super creamy. Fun to throw down a blob onto a greasy pan with a "splat" and scrub it all around, watch the grease disappear. Woohooo!