I was on a trip where someone used a five-gallon paint strainer bag as the dishwater strainer. He'd put it in a bucket and pour the dirty dishwater in it. Pull it out, and turn it inside out in the trash.
It worked well enough, but left that one bucket really greasy so that it couldn't be used to fetch water for other purposes. Kind of gross.
We also had "garbage bag salad" on that trip. Also a neat idea, but I'd do it in a food-grade bag if I ever did it again. Cut up all the vegetables, and throw 'em in the bag. Add dressing and shake. Serve. The leftovers, if any, are already packed. But garbage bag? Yuck. Definitely not food grade, and maybe even treated with anti-odor and pesticides.
If my LAST post didn't address the original question, this one SURE didn't.