Recommendations for Cleaning Alkyd and Latex Paints
Flat paints have a high pigment to resin ratio, and the pigments are usually not entirely covered and protected by the resin. Unless adequate care is taken, washing of flat paints can lead to burnishing or polishing of the cleaned area, leaving it visually unacceptable.
Use only mild soaps, such as dishwashing detergent, and liberal amounts of water for cleaning and rinsing.
Medium and dark colors in flat paint do not wash well, since burnishing cannot be avoided.
Eggshell, Semi-Gloss and Gloss Paints
As a general rule, the higher the gloss, the better the wash-ability. These paints have enough resin to prevent burnishing.
Do not use abrasive powdered cleansers such as Ajax or Comet, since they may scratch or cause the surface to go flat.
Do not use cleaners containing ammonia on alkyd paints. This can cause permanent yellowing of the finish.
When using Tri Sodium Phosphate (TSP) follow the package instruction. Strong solutions of TSP in warm water will de-gloss alkyd paints.
Most other cleaners are effective in cleaning these surfaces without damaging the paint finish.
Courtesy of PPG Architectural Coatings