If it is grease your talking about, that needs to be removed first. If the walls were painted with a gloss or semi-gloss paint, either oil based or water based, it must be de-glossed first. You can tell if you stand next to the wall and look at it. If you see a sheen, you can rough it up using 150 grit sandpaper. A quick go over will do, no need for a major sanding job. If the wall has no sheen, it is a flat paint and you can paint directly over that after washing off the grease. I use 1 cup Ammonia, 1/2 cup Vinegar, 1/2 cup Baking Soda to 1 gallon of hot water. That is the best thing to clean wood, walls, trims and moldings with. No need to rinse afterwards.
Why do people think bleach will clean everything? It won't shift grease, so wash the walls with a detergent.
The dust is for the most part gone (cleaned to my best ability) however, my walls are still dirty. Dirt that just will not budge! Can I just paint over it?
