On Tue, 17 Nov 2009 10:21:45 -0500, "
wrote:

Ray K wrote:
wrote:

It sounds like the stains are oxidized aluminum. Repaint.

Definitely not oxidation. When I tried rubbing alcohol applied with a
paper towel, it made a noticeable improvement, but took a lot of
pressure. Also, that would be expensive to treat 158 feet.

Alcohol would probably have softened the paint and might behave as you
describe. There is a difference between dirt and stains...oxidation,
polution, roof runoff, etc., can cause stains that become part of the
paint film.

Overall, the first thing I tried (bleach with laundry detergent) made a
noticeable improvement, but not as much as I'm looking for.

Alcholol won't soften the baked on paint of the aluminum gutter.