On Jul 29, 2:35*pm, Matt wrote:
I recently moved into a new house. *Several of the exterior vinyl
windows have these strange fingerprints on the outside of the upper
pane just above the meeting rails. *I've tried cleaning them with a
razor blade, soap and water, Windex, Simple Green (full strength), Goo-
Gone, Goof-off and Turpentine. *With tons of elbow grease, I'm able to
get the fingerprints off - with no one product obviously dissolving
whatever the fingerprints are made from. *Still, when I go to clean
the window afterward, just spraying a soapy solution to squeegee, you
can clearly see where the fingerprints are - even though the window is
mostly clear. *I have 19 windows to go and dread the thought of having
to spend 15-20 minutes on each getting these prints off and even then
- not really getting them all the way off. *Any ideas what they could
be and what would dissolve them without damaging the glass or windows?

Try these things, in this order, or based on what you already have in
the house.

WD-40
Lighter fluid (Rossignol or Zippo, not charcoal)
Acetone