I have the solution finally. It is almost impossible to carry a wash rag in my backpack. It gets too smelly. Unlike a towel that is only slightly wet, a wash rag is very wet. I cannot get it dry by the next time I leave. Just a hassle. I purchase a very light sponge, and it wringes out almost dry. Much lighter then a wash rag and does a good job. A cheap and easy way to clean my world or grime or persistent culture.