Streaks on windows
 

When I roll back up my windows from being down there are small mostly vertical diagonal lines, anyone else experience this and any suggestions?

I did on both my 986 and never figured it out. I posted on here about it as well. Almost as if there is some sort of water or oil res in the door that is hitting window or something. Mine was alway right around the door handle area...meaning if you put a ruler on the line that was created it would drop in that area.

Mine is fairly consistent across the window, from edge to edge and it happens on both sides. Always wipes off, however, it is odd and frustrating.

My '07 Cayman S used to do the exact same thing.
When I would ask the dealer about it they would make up some lame excuse or twist it around and blame it on something they said I must have done.
Had the car for 4 years and never did figure it out.

Luckily my '01 Box does not do the same thing.

I have one on each side, annoying but, just keep the windows down:D

Sounds like the window scrapers/seals need to be cleaned.