 and you let it soak, and you rinse it off, and it cleans very well. It's like an engine degreaser, but it's going to remove grease, dirt, dust. It's got an anti-static in there to try to prevent dust from building up in there. So it's worked well for me on both the home air conditioner and on cars to clean. I sprayed some on our Tahoe in between there to try to clean that off, and it really cleaned it well. Is that a big old copper radiator in there? Yes.