Can't specifically address NW moss.....
But there is a product called Jomax House & Mildew Killer that is VERY effective at removing mold/mildew here in the SE. �Spray on......wash off, minimal scrubbing.
I buy it at the big box hardware store, certainly you can find it via their website etc. �It is made by Zinsser which is a Rust-oleum company. �Google Jomax.
Anthony'89 Syncro GL (Hidalgo)

--- On Wed, 5/18/11, Todd.Last <Rubatoguy@COMCAST.NET> wrote:

From: Todd.Last <Rubatoguy@COMCAST.NET>
Subject: Moss removal
To: vanagon@GERRY.VANAGON.COM
Date: Wednesday, May 18, 2011, 11:57 AM

Any tips on what is the best way to remove the pacific northwest green
moss stuff that likes to try to take hold in the rain gutters and such?