I have seen this before. In my case it happened with a certain DE-GREASER formula like Greased Lighting but an off brand.
When used on certain metals like Aluminum at above average warm and cold temps they can leave "stains", I actually stained my stainless steel sink with it. Then read the directions and it said that on there!
But they work SOOOO well on the wheels and especially the tires. But you can't let it dry or it will leave a milky film. You have to use more and then hose off before it dry's again.
They probably sprayed some of it on there on a warm day and didn't get it off fast enough.
Cory Russell
When used on certain metals like Aluminum at above average warm and cold temps they can leave "stains", I actually stained my stainless steel sink with it. Then read the directions and it said that on there!
But they work SOOOO well on the wheels and especially the tires. But you can't let it dry or it will leave a milky film. You have to use more and then hose off before it dry's again.
They probably sprayed some of it on there on a warm day and didn't get it off fast enough.
Cory Russell