Cleaning walls before painting is an essential step to ensure that the paint adheres well and provides a smooth finish. Here are some tips and tricks on how to clean walls before painting:

1. Remove dust: Start by removing dust and cobwebs from the walls using a duster or a vacuum cleaner. Start from the top of the room and work your way down to avoid dusting more than once.

2. Wash with soap and water: The best cleaner for walls before painting is warm water and dish soap. Use a sponge or a soft rag to gently scrub the walls in a circular motion. For greasy kitchen walls, you can use warm water and a little dish soap. If you have stubborn spots that are not responding, you can use one of the cleaners recommended by paint manufacturers based on the paint finish.

3. Rinse the walls: After washing the walls, rinse them using a slightly damp cellulose sponge.

4. Let the walls dry: Allow the walls to dry completely before painting. You can use a fan or open windows to speed up the drying process.

5. Protect the floors and furniture: Cover the floors and furniture with drop cloths to protect them from paint drips while painting walls.

In summary, the best thing to wash walls with before painting is warm water and dish soap. You can use other cleaners recommended by paint manufacturers based on the paint finish for stubborn spots. It is important to remove dust and dirt from the walls before painting to ensure that the paint adheres well and provides a smooth finish.