Washing a fiberglass airplane

Hi all,

After a year of heavy use, including multiple applications of that nasty
orange deicing fluid, my Diamond Start is dirty is hell. Technically it is
not even white anymore. I want to give it a wash for the first time, but I
want to do it properly.

Our airport has a wash station with water hoses etc. but I guess I need to
apply some "shampoo" on it first. I know I need to use silicone- and
oil-free substances, but what kind, and how do I use them exactly?

If someone could describe how they wash their plastic airplanes in detail, I
would appreciate it greatly.

-- City Dweller