I've got a 2001 S80 with aluminum alloy wheels.

My car is usually kept pretty clean but inevitably 2 or 3 days after a car
wash the brake dust begins to build up and becomes noticeable no matter how
clean the rest of the car is - but that's perfectly normal and not the point
of my question.

Today my wheels are dirty and I happened to see something on three of my
four wheels that defies description, and which I've never noticed before:
each of the three has at least one mark that looks like somebody has swirled
something against the wheel and made a shiny round spot amidst all the dark
brake dust.  One wheel has two such marks.  Two have one each, and the
fourth has none.  They are not all the same size.  They range from about
5/16" diameter to perhaps 7/8".  All are near the outer edge of the wheel
within an inch or two of the tire.

Does anybody remember an old metal decorating technique known as "engine
turning"?  Well that's just about what this looks like.  The marks look like
the result of a deliberate act - but that's impossible.

I certainly didn't do it myself and the car is never parked in an area where
it might be vandalized.

I'm stumped.  I have no idea what could cause something like this.  I took
some digital pictures if anybody wants to take a peek and offer some kind of
explanation.

Reply to the group.

Pat