Skipper Buds pulled my boat out last week and power/acid washed the bottom for me, put it on my trailer and parked it out in the lot where they were piling up boats for winter storage. When I picked up the boat, there was black, sooty-looking stuff covering the deck and cockpit cover.
We thought it was just exhaust stuff from the diesel fork lift or giant boat lift, but it didn't come off with the soap and brush approach. A small rubbing compound test didn't produce much results, either.
Anybody have any idea what this stuff is and how it can be removed from both the deck and cockpit cover?

I have had similar stuff on my boat at my marina.
Thought it was from the diesel boats in front of me?
Seemed to only get on the boat right after I washed though...

Bob,

Try a solution with some orange-glo / citrus type of cleaner in it. I have a car that I have purposely running very rich and I get the black exhaust soot on my back bumper cover. Using the cleaner with the orange-glo, it comes right off with one wipe and no rubbing. Normal cleaners would not / could not get it off.

- Jamie

Maybe a semi trk that started up close by and with all the wind we had last week. I used to always see this when selling trucks on the lot.

Did you try some mild hull cleaner like Stabrite?

Bob, After looking at it today....I think #50 Cleaner/Wax would clean her up real good.
BTW, Thats one nice Boat.