Cleaning Sails

[High Pointer]

My main is under a sail cover all season,mud wasps keep building mud nests
4in,they fall off when the main is raised but leave the mud stain behind.
One of our local Sail Cleaner uses a power sprayer for cleaning.
My thought is,if I hung it horizonttaly and spray a wide spray with what??
It grayed a bit the last few years would a stain remover(oxy)
spray followed with a (soap) spray then rinse spray..
Have of you any suggestions as to what works best from your
personal sail cleaning?