In our pump room we have some lighting wires that are taped off above the two IMO pump motors (next to the ladder). IMHO, we should reconnect them to the lighting fixture and get a light screwed in. The light fixtures should be the only live wires down there, at the moment. Same with the lower engine rooms. As long as we don't aim the pressure washer at the ceiling, we shoudl be fine.
My main concern is the nasty fluid that collected near the periscope bases. It should be tested for hydraulic fluid contamination before we start spraying - nasty stuff. Even if it's oil, it probably should be cleaned up as best as possible.
We have some open pipes and a compressor with it's top cap missing that would also have to be sealed off. Plastic bags with bungee cords or duct tape should work fine.
And last but not least, get Mike Rowe to do all of it.