Best, safest way to wash walls without removing paing?

Doing house cleaning for a chain-smoking friend. Walls are covered with yellow film but I need to wash them since the house is on the market. What is the best way to get this stuff off without removing the paint? Repainting isn't an option for this owner, though the new owner might choose to, so far everyone wants them washed.Best, safest way to wash walls without removing paing?
My mom always used vinegar water. IT seemed to do the trick! It'll help with the smell too! Also, if the place stinks, you could try putting bowls of vinegar or baking soda around the house to absorb the smell. Just make sure they are out of the way of animals and kids.





Cheers!Best, safest way to wash walls without removing paing?
We used ammonia and water when my friend and I rented a prior smokers house. It worked great.