I learned about using Murphy's in the 90s when I was a scenic painter. However, for some reason it did not occur to me to use it on my personal art brushes until I took a class with Robert Burridge who recommended its use to his students.
Soon after that I left a cheap throw away brush in a container in which I had mixed paint and a little water. There wasn't much left and I suppose I thought I might finish it off. I didn't and it ended up completely dried and bent to the shape of the container. I thought, aha this is a test for Murphy's! So I covered it with water put some oil soap in with it and let it sit for a day or two. With some effort, but not a lot, all the paint came off and it was better than new. I was amazed!
The metal container shown next to the bottle of Murphy's wood oil soap is great for holding brushes so that only the bristles hang down into the water and oil soap mix when soaking is necessary. It's best not to leave brushes soaking in any kind of water for long, and I have an assortment of abused brushes to prove it. The above container is also good for letting brushes hang upside down out of the water to dry.
As you can tell from the paint stains, I have used that container for water while painting, but the two shown below are my favorites. The round one with the vegetables on it was a dish that belonged to my grandmother. It has a crack down the side so it was no longer good for food but has been excellent for holding rinse water. I think I've been using it since I started painting.
It is best to wipe excess paint off of a brush before it is rinsed. I've used paper towels, but I prefer to use items that can be reused such as washcloths, pillowcases, and T-shirts. Sometimes this causes beautiful and interesting results as seen below. Dried acrylic won't wash out and is often soft and pliable. However, mediums and thick blobs of paint can be stiff.
When I finish with my rinse water I dump it into a five gallon container. That way the water can evaporate and the acrylic sediment can eventually dry and be thrown in the trash. This keeps as much as possible out of the drainage system and the sea.