black spots..dots..speckles on exhaust pipe?

[zeke]

Gents. While doing an oil change today I noticed some black speckling spots on the exhaust pipe. I have heard of the bluing that can happen to the headers but this is occurring on the section of pipe closer to where it connects to the cat.It seems there is more of this speckling on the left pipe than right. Any ideas?

[towerworker]

Are you certain it's not just road tar or the like?

[zeke]

I do not think it is road tar or anything like that. I'll try to get a photo. It is hard to describe. Maybe stipulating would be a good word to describe what I am seeing.

[Buckster]

Are you certain it's not just road tar or the like?

That's what I was thinking too. More on the left because of the camber on most roads tapers to the right for water drain off.....

[zeke]

You bring up a good point. I'll try cleaning the pipes to see if that was the source of the discoloration. Next question, what do I use to clean these things? I am sure the auto parts store has something, but any suggestions are welcome.

[gregor]

I'm not fussy about shiny exhausts so use a wire brush if there is any slight corrosion on the exhausts/headers. Black spots are butumen/ashphalt/pitch or whatever is used on the roads. White spirit and turpentine is the stuff to remove it. The shiny rear end gets plenty of black spots.

[Bruce H]

I don't think I'd use a wire brush but citrus cleaner works on road tar spots as does chrome cleaner.

[Ol' Jeffers]

I use a worn nylon scouring pad and Solvol Autosol first and then Maguires or similar.. It requires a lot of elbow grease to shine them up
but they can be made to look as good as chrome. It helps greatly if you have access to a motorcycle bench!