How to clean mobile home walls?

Clean them as you would any other wall. Manufactured homes have no special materials that are different from any other structure.

Chances are the wall panels are like the one I owned, vinyl wrapped gypsum board. They are more moisture resistant than wallpaper. A rag, bucket of water with Lestoil, Pine Sol, Murphy's Oil Soap, or any other cleaner you like, mixed according to directions.

Wring the rag out until nearly dry so you don't get runs down the wall. Wipe the wall. Rinse, repeat.

Better yet, slip the pool boy a twenty and have him do it.

I never got very far with that type of wall covering if it's before the paper cover was vinyl. A fresh coat of paint from the "oops" section in a satin finish will make 1000% improvement and will be washable after.

I agree with Simbalg63. You might be better off to put as fresh coat of paint over the paper covering. It is very hard to clean it once it has aged that long. Cleaners that have water in them will most likely cause the paper to get stained or damaged. If painting is not an option, try using a soft cloth with a bit of all-purpose cleaner like Simple Green or 409 on it. Make sure the cloth is not very damp or it may damage the paper covering.

https://www.ehow.com/how_6301788_clean-mobile-home-walls.html

There is a dry sponge/eraser that is used to clean delicate surfaces. You can find it on Amazon.

I use a 50/50 vinegar water solution for tougher stains I add teaspoon of dawn dish soap to the gallon mix.