Im a BIG fan of the Magic Erasers but they do take the paint off of these walls. There are a few places though that had bad scuff marks and I used it anyway.
I talked with a lady that used to paint apartment buildings for a living and she told me that they only thing that I can do is use warm, soapy water and a sponge, then only wipe in ONE direction while wiping down the wall. While it works a little to clean the wall, it doesnt work to take off scuff marks or any places that have really dirty places on them.
The owners of these places will be back in town in a couple of weeks so Im going to ask them how they would like me to tackle this problem. My suggestion will be to paint in a semi-gloss. If they will pay for the paint, we will do the painting. My biggest problem is the wall going down the steps from upstairs. My DD holds onto the wall to walk down the steps so you can see finger prints all the way down the wall---not to mention the scuff marks from the previous tennants.