Hi professionals,
I have 2 separate ductless systems (installed about 5 yrs apart in different areas of our house). I have never done any exterior maintenance on them, but feel like I "should".

When I bought the second one, the sales guy said it was so easy to maintain the exterior units--just use a little cleaner and spray it down with a hose. Well, that sounds too easy! Which kind of cleaner? I assume I need to power down the unit? Anything else I need to know?

It has been suggested that I should use a green cleaner. I just want to make sure it won't be corrosive or too detergent-y for any greased mechanisms.

I've called some local companies that offer "ductless maintenance", but they are ridiculously priced for a simple cleaning! When I ask the gal on the other end of the line what they do for a ductless system clean, she goes on about cleaning the ducts... Um "DUCTLESS". Then, she says, she'll have to get back to me (and has never done so).

So, what do you all do for exterior unit maintenance? I live in the pacific NW where it is soggy many days of the year, so algae/moss can become a problem, at least on the shell of the unit.