Pour a cup of laundry detergent into a full bucket of warm water. Mix the detergent and water completely and dip a soft bristle brush into the water. Rub the painted surface vigorously with small, circular motions. Rinse the area thoroughly.
Add 1/2 cup of ammonia to warm water and mix. Use a soft brush to scrub the paint lightly with the ammonia. Rinse thoroughly to dilute the ammonia left on the paint when done.
Pour chemical stripping compound onto a damp sponge. While wearing rubber gloves, wipe the paint in smooth, long strokes, always in the same direction. Rinse the cleaned area with strong spray from a garden hose to force the chemical stripper away from the paint.
Attach a fan-spray wand to a pressure washer. Set the washer to no more than 2,500 PSI. Stand back from the painted surface approximately 5 feet and spray the water seal to remove it.