It just doesn't create a problem at all, it's just one of those ugly little things. I do have one friend that it really bothers. You would think the sky is falling if he has baked on castor stains on his muffler. The Dawn really does work and it isn't caustic, even smells pretty good. Not sure you can get in in your country or not but it works. I even have some in my shop and I have never bothered to really clean an engine. For some reason mine just don't get a lot of the nasty crud on them except for the mufflers on my four strokes?? Can't see it in the air. I live in a desert too and it really isn't a problem with over heating.