Mix a solution of water and a mild detergent.
Clean the wall with the soapy solution. Flakes of paint may fall from the wall; this is to be expected with a crackle texture. At this point, remember that cleaning the wall of dirt and grease is most important, as sanding will remove the rest of the paint.
Let the wall dry thoroughly for one or two days. To speed up the process, direct a floor fan at the wall.
Repair any holes or cracks in the wall with caulk.
Sand the wall with fine-grit sandpaper until the surface is smooth to the touch. Prepare to go over the surface more than once, as there are three coats affixed to the wall.
Wipe the wall with a wet sponge and let it dry thoroughly.
Apply one coat of acrylic primer to the wall with a roller. Allow it to dry for at least two hours.
Apply two coats of paint and let dry. If the wall is in a high-traffic area, apply one coat of acrylic varnish to protect the finish.