I use liquid detergent for laundry. I get the big thingy at Costco. It works for me. But then, when the container is empty and needs to be thrown away, I think of all the "air" it's using in the trash. And so I thought of a useful idea to use up that "air" and do some good in the world. Just kidding. I read on a preparedness blog how to use the empty container for storage. Use the last bit for your load. Then fill the container with water. Put the lid on it.
Write "do not drink" on the container. That way there won't be any confusion. When hit with a tornado or earthquake or other such natural disaster, you have detergent water handy for dishes, dirty hands or feet, or just about anything that needs a quick wash. You really wouldn't use it for laundry. It's not enough detergent to do anything justice. Unless you are desperate.
So there you go. A useful storage/cleaning tip for emergencies