Fill a bucket with 1 gallon of warm water. Add 1 cup household ammonia.
Dip a flat sponge mop into the cleaning solution. Wring out the mop well so that it is not dripping wet.
Start cleaning walls from the top and work your way down. Stand about two feet from the wall and scrub with the mop. Work in three-foot-wide sections and scrub from the top to the baseboards.
Dry each section promptly after washing it. Wring out the mop very well and place a dry towel over the mop head. Run the mop over each section to dry it.
Continue scrubbing and drying, working in three foot sections, until the entire wall has been cleaned. Rinse and wring out the mop often.