 We tell people don't use anything stronger than a garden hose or your thumb over the end of it because you're going to bend those fins. So you've got a very expensive, very large radiator. We would suggest do that first. Even compressed air can bend those. And when you bend them a little bit, if you reduce that, let's say, by 10%, just watch your temp gauge go up 10%. You don't want to do that. So get it as clean as you can by hand. And then what I found is very effective is