cleaning painted walls

My walls tend to "yellow" over time, with a smoker in the house. So I decided to wash down the bathroom walls. I had recently discovered how much I like Greased Lightning as a cleaner. So I used it. Afterwards, I read on the label to not use it on paint. Sure enough, my walls look like tiny alligator skin.
So what should I use to clean my walls. This yellowish stuff is a bit gummy, perhaps from cooking fumes, so I think the cleaner needs to cut grease. Any ideas?