I've been doing this for years.....the trick is to do it when the wife is not at home! Also, to clean a cooling system, drain the anti-freeze and flush it all out. Then mix about 1 1/2 cups of powder,(1 cup liquid) automatic dishwasher soap in about a gallon of water. mix it well, and put it in the radiator. Just drive the car a few hours and get it good and hot, (Dishwasher soap is VERY powerful, but doesn't start to work until it's at least 140 degrees). Let the engine cool, and flush it out with clean water and re-fill with anti-freeze.
Don