Scratching a wall for painting: What I need to know
When it comes to painting your walls, there is more than meets the eye. Scraping a wall for painting is an important step that should never be overlooked. This process involves removing previous layers of paint, wallpaper or other materials from the wall in order to create a smooth and even surface for the new paint to adhere to.

The first step in scraping a wall for painting is to identify any existing layers of material that need to be removed. This can be old paint, wallpaper or other materials such as wood or tiles. Once you've located these materials, you can start scraping them away with a spatula or other scraping tool. It is important to be careful when scraping these materials so as not to damage the wall or surface.

See the article here