Based on Jackdaw's recommendation, I ordered up some Amazing Roll-Off cleaner. Or, as I like to call it now, "Clay's Magical Boat Elixir." 
I wasn't too sure if I was supposed to spray it directly on the boat, but there were also directions to make a really dilute mixture. So, I wound up making a not-so-dilute mixture for my spray bottle, because the math of getting it right according to the bottle seemed a bit beyond my measuring tools, and also seemed really weak.
In any case, I wet the deck, sprayed on the stuff, let it sit a few minutes, magic happened, scrubbed a small bit with a brush, and rinsed off. On areas that I thought were pretty clean already, the Magical Elixir proved me wrong, lifting up a good bit of grey suds and water.
In the week I've had the boat out of the water, there was plenty of time for oak leaves to sit in the cockpit, and rain to make 'em wet. The Magical Elixir was not very effective at getting the leaf prints out of the cockpit sole, but I'm not worried about that. If next season's sun doesn't bleach them out, the Mary Kate's On and Off waterline cleaner will make very fast work of the stains. Then again, spraying some Magical Elixir right on them might work too.
So, thanks a whole bunch, Clay!
I wasn't too sure if I was supposed to spray it directly on the boat, but there were also directions to make a really dilute mixture. So, I wound up making a not-so-dilute mixture for my spray bottle, because the math of getting it right according to the bottle seemed a bit beyond my measuring tools, and also seemed really weak.
In any case, I wet the deck, sprayed on the stuff, let it sit a few minutes, magic happened, scrubbed a small bit with a brush, and rinsed off. On areas that I thought were pretty clean already, the Magical Elixir proved me wrong, lifting up a good bit of grey suds and water.
In the week I've had the boat out of the water, there was plenty of time for oak leaves to sit in the cockpit, and rain to make 'em wet. The Magical Elixir was not very effective at getting the leaf prints out of the cockpit sole, but I'm not worried about that. If next season's sun doesn't bleach them out, the Mary Kate's On and Off waterline cleaner will make very fast work of the stains. Then again, spraying some Magical Elixir right on them might work too.
So, thanks a whole bunch, Clay!