If they're painted with water based paint.
Water based paint can be washed if it is glossy.
In either case, once the paint has dried, water won't dissolve it. The latex has already polymerized, or whatever it does.
I'm wondering if plaster has some kind of effect that would of maybe caused this too. I was cleaning an area I plastered so some plaster got on the rag too. At first I thought the plaster was just spreading on the wall making it look like I was taking off paint, but then I saw the paint color on the rag. The wetness made it look worse though, after it dried, it's not even noticeable that paint came off.
I actually have a magic eraser, I'll have to try that next time.
I'm wondering if plaster has some kind of effect that would of maybe caused this too. I was cleaning an area I plastered so some plaster got on the rag too. At first I thought the plaster was just spreading on the wall making it look like I was taking off paint, but then I saw the paint color on the rag. The wetness made it look worse though, after it dried, it's not even noticeable that paint came off.
I actually have a magic eraser, I'll have to try that next time.
magic eraser still uses water.