[Jaidyn]

Try one of these. I used the corn starch one, and it worked. Grease removal

[Zionist Conspirator]

Try one of these. I used the corn starch one, and it worked.

The article says "before painting." These walls are painted already.

[llevrok]

I’ve known people to use wood pulp (bleached cellulose) and get it damp enough to make it paste-like. Then put it on a wall or masonry.

When the stuff dries, you brush it off. It has wicked up all the grunge and grim from the surface.