Take off the lower radiator hos and drain. Fill with water and flush. I did it a couple of times until clear water came out. Re-fill with the proper mixture of Dexcool, remembering that you will not get all of the water out of the block when you flush unless you remove the block drains. Then make sure to bleed the system proprerly.

For the p/s, easiest way is to take a turkey baster and suck all of the fluid out of the tank. refill, drive around and repeat.