WOOLITE.....WOOLITE......lukewarm water and a good little brush.
Pressure washing will destroy the fill and it will leak. Regular detergent will damage it too. Don't use the oxalic either.
From the supplier:
Sunbrella: Marine tops and covers
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)