flushing a heater core

RedFish said
Everyone does things differently. I drape both heater hoses over the fender and switch the clear water supply direction repeatedly until the outbound runs clear.
I wont over attach the water supply ( garden hose ) to any part of a vehicle cooling system. Average pressure of public water is 65 p.s.i.
A lot more than the parts were rated for .

And that's good advice. I left out the part about not turnin it wide open. Sometimes I take for granted people will figure it out on their own. They might not. Thanks.