I should have been more clear... wash isn't so much for panels.. mostly for the interior. sea grass flooring and Simtex seating... even the bimini and mooring cover..
Oh..I thought you meant exterior as well. Not sure why any interior cleaning would run off into lake unless you want to spray clean these areas somehow…which I guess I just wouldn’t do with most of the items you listed.
For us without a trailer and boat docked lakeside seasonally on its sea legs:
1) Simtex: just follow cleaning directions with a bucket of water and hand towel, and approved cleaning agent if needed. Ours turns out fine doing it by hand this way. No run off into the lake using hand towels and a bucket of clean water for rinsing towels.
2) Mooring cover: It can just be removed and cleaned shoreside. No need for lake run off, and I don’t think you could get it cleaned well on the boat anyway. I would not use any pressure sprayer on it myself, and I wouldn’t want to use a scrub brush on a long pole unless its flat on a hard surface such as a yard, driveway, deck, etc… We clean ours at the end of the season, lakeside in the yard with some scrub brushes, a bucket of dish soap and a bucket of clean water, with just our yard hose.
3) Bimini & bimini cover: we wipe it down by hand with a bucket of water and sometimes dish-soap & water during the boating season. If the top of it needs cleaning, we remove and do it in the yard lakeside like the mooring cover at the end of the season. However, 90% of the time if we are going to have a hard rain with low winds, I will leave the bimini deployed and Mother Nature basically scrubs it clean for us. That said, ours is also only deployed about 10% of the time, mainly in August. Thus, it rarely gets dirty and we have only had to “clean it” once in the yard.
4) Sea Grass: we don’t really seem to need to do much of anything. I have literally never “cleaned it”. I use a leaf blower to blow stuff out/off, and if anything gets “in” it, I just spot clean the area by hand (which has only been necessariy a couple times in 7 years for us). Others in here have talked about scrubbing and using a very gentle power wash or water sprayer. We don’t get sand or mud on it due to the nature of our lake house shore and lake, so we are inexperienced in ”needing” to clean it.