What's the best way to wash dark painted walls?

I've tried regular wall washing methods but it leaves streaks on my walls. I have a chocolate brown wall and a dark purple wall that I can't get clean. Anyone know?What's the best way to wash dark painted walls?
It's really a two person job as you've got to work quickly and change water often. Start by mixing 2 ounces dry measure of trisodium phosphate (TSP) per gallon of water. If you're doing kitchen walls, add a 1/2 cup of ammonia per gallon of water.





Each person needs a bucket and a long-handled sponge mop....gloves and probably goggles as liquid flies and TSP isn't nice in the eyes. Start from the bottom and work up. One cleans and the other comes behind and rinses. Change the rinse water at least every wall......maybe twice if a big wall. Watch the wash water, it too many need frequent changing.





Indeed, the duller the finish on the walls, the harder they are to wash and dark colors are worse.





(owner of some purple walls too)What's the best way to wash dark painted walls?
I've used ammonia/water to wash my walls and it worked great.
Sugar soap.