35% Hydrogen Peroxide mixed at 1:50 should do the trick.
"frank stefek" <frank.stefek at btopenworld.com> wrote in message
news:b213hq$k8o$2 at sparta.btinternet.com...
> One of my customers has a big problem with moss on his roof and walls.
> Can anyone tell me of a good Moss Killer witch is easily obtainable and
> to use?