Finally, having ensured your walls are in a good condition, it's time to wash them down. Using sugar soap is the most effective way to wash walls prior to painting as it cuts through grease and grime easily, dish soap can also be used with warm water if sugar soap is not easily accessible.
Stick with Warm Water or Mild Soap
If you have stubborn spots that are not responding, you can use one of the cleaners they recommend, based on paint finish: Flat or matte paint: White vinegar or plain water. Glossy paint: All-purpose cleaner or dish soap and water. White paint: Baking soda and water.
Sugar soap is essential for cleaning the walls before painting them.
Gently rubbing the walls with a dry sponge is your best bet. Or, tread lightly with a cleaning solution of water and mild dishwashing liquid soap (a drop or two of dishwashing soap per half-gallon of water).
Once you have removed any old paint or wallpaper, wash down the surfaces that you plan to paint with diluted washing-up liquid and hot water. If you're painting the kitchen, there may well be grease on the walls, so try using a slightly stronger solution of washing-up liquid.
Sugar soap is a cleaning agent and can be effective for removing stains, grease, and loose paint flakes. Sugar soap can also rejuvenate painted surfaces but you need to be very careful to avoid removing too much paint or damaging the surface.
Cleaning Walls
Mix together ½ cup of vinegar and 2 cups of warm water. Put the solution into a spray bottle, and apply a light layer onto the wall (don't oversaturate it).
Mix water and dish soap
Now that the dust is wiped away, it's time to wash walls. Fill one bucket with a gallon of warm water and mix clear liquid hand or dish soap and water in the other. Soak a cloth in the solution, and wring it out well.
The paint won't adhere properly and you will be left with a poor finish. Properly applied sugar soap will make sure that this doesn't happen.
You can use sugar soap or just a bit of washing liquid, sugar soap needs a fair bit of rinsing sometimes. No need to thin the paint unless it's a bit thick that's for misting on new plaster and 50/50 is too much anyway.
Sugar soap is great for washing walls, but for a cheaper sugar soap alternative, dishwashing detergent and vinegar do the trick. Put some warm water in a bucket with a squirt or two of dish detergent and a splash of vinegar. With your rag, wet it in the soapy water and wring it out so it's not soaking wet.
Remove any nails or hooks from the wall, then use sandpaper to sand over any rough or flaky bits. Dilute some Sugar Soap in a bucket with water (as per packet instructions) and use a cloth to wash off any dirt, dust and scuff marks. Done!
Wall Cleaning Tips
*The gentle cleaning solution of vinegar and water detailed below is great to use for washing walls as a prep before a fresh coat of paint as well.
Baking soda – Made into a paste as sugar soap alternative
Half a cup of baking soda to about 1 bucket of water. Dry wall well, don't soak!
You won't have to rinse afterwards, unlike the soapy water. White vinegar solution and detergent solutions work especially well for walls with oil-based finishes. But if the wall is texture-painted, then you might require a bit more deep cleaning.
You can also use most non-abrasive multipurpose cleaners on this type of paint or make your own by mixing one teaspoon of liquid dish soap and ¼ teaspoon of white vinegar into one quart of water. This cleaner should work on most latex paints. Finally, oil-based paints can take a slightly stronger cleanser.
Rinsing is not necessary! If you're simply using a vinegar and water solution to wipe and disinfect, you won't need to rinse. However, if there's also plenty of dirt and grime you're wiping away, you may also want to rinse with some extra water.
Consider the advice of the major paint companies: PPG: "Wipe walls clean of dust and dirt." Behr: "If you need to remove any oil, grease, or wax stains, apply a mild detergent with a sponge onto a lightly water-dampened surface, rinse with clean water and allow it to dry."
For most painted walls, warm water and dishwashing detergent will work well, but if your walls need more substantial washing, add one cup of white vinegar to a bucket of warm water. Vinegar will not be harmful to the paint on the walls, so do not worry when applying how to clean the stain on the wall with vinegar.
It gets the name because, in powder form, does look a bit like granulated sugar. It is just a mild detergent which is especially useful for preparing paintwork because, once it has been rinsed away, will not leave behind any residues that may hamper the adhesion of your new coat of paint.
You probably don't need a primer. If the current wall is smooth, clean and covered with the same type of paint (both are oil-based for example), you can head straight for the paint. You need to fill holes, spackle and sand*, maybe even cut a new piece of drywall in to the existing wall.
If a wall has a mould buildup that has gotten under the paint often the only way to remove it is by painting over it. When it comes to using sugar soap beware: whilst it does help clean walls it can also leave it with a fine buildup.