Before painting, clean walls with white vinegar and let dry before painting. Inexpensive and easy. Also put your paint brushes in white vinegar and rinse well and dry before using.
By Sandi G (s222)
Vinegar is a great nontoxic cleaner. The tip did not say to cut it with water, or rinse it off. In any case a very important step for a good paint job is the prep work. A clean surface with out grease, dirt or dust is essential. I also move furniture that's in the way, tape off areas I don't want paint on, use drop cloths. Actually the prep work is almost as much effort as the painting, but it makes a big difference in how your project will turn out. Otherwise you'll end up cleaning paint splatters etc.