Thursday''s Ask the Experts question from a cleaning professional on the International Custodial Advisors Network (ICAN) "Ask the Experts" page: We have a bank of skylights that were covered with a film of black soot and grime. We cleaned them and from the outside they looked fine. When we went inside to check them, they looked awful. You wouldn''t even think they were the same windows. There were swirls, streaks, and mysterious looking crop circles on the inside of the windows. The skylights have been there over 20 years. I can''t even get a window cleaning company to come out and look at them; they just laugh and hang up. Are these skylights damaged beyond hope?
After 20 years, there may be some glass etching from the harsh outside environment or damage from previous cleaning attempts over the years. The swirls and circles sound to me like attempted hand-cleaning efforts. Rewash the exteriors if you wish, but take a close look at the insides which may be more difficult to reach and work on. Possibly, this is where the marks you describe are and you may need scaffolding or a lift to get to them and clean them effectively. After cleaning, dry and polish with a microfiber cloth to see if this makes any difference. Many window cleaners are not properly equipped and don''t want to mess with a small job as it is not profitable for them. This may explain ... — Lynn E. Krafft
, ICAN/ATEX Editor