Degrease the Surface
There are a lot of benefits that come with degreasing your surface before painting. Usually, degreasing is done for metal surfaces to clean the surface and remove rust and grease that might get in the way of painting. Similarly, it would be best to degrease your walls before painting to remove any grime or oil that can hinder your paint from adhering.
Although there are a lot of degreasers to choose from, liquid T.S.P is highly recommended for degreasing surfaces. This liquid is also an all-purpose cleaner designed to cut through grime and grease from indoor and outdoor surfaces. This concentrated product can also remove paint from brick and concrete, making it an excellent choice for when you want to prep walls for painting and wallpapering.