This brings back memories of when I was 12 - found a gas can half full in the woods behind my house. Don't ask me what I was thinking, but I poured every chemical from my chem set into it to see what would happen. I mentioned it to my sis, who mentioned it to my mom, and the next thing I knew the bomb squad was there removing it. Oops
I'm leaning towards the synthetic methods right now... or just removing them and sending them out for cleaning and then rebedding them (I can't tell if it's dirt or disintegrating compound around the starboard side chock in the picture).
What do these things look like clean?