I'm of the -let sleeping dogs lie- camp. But all the horror stories I read on these forums, have me thinking I should take a peek. I have pretty good records that nobody has been inside the 80 gallon fuel tank in my boat for the last 30 years. I even suspect, the steel tops(huge plates with about a 100 bolts through the fiberglass flanges), which are bolted over the integral hull tanks in the bilge, have not been off since 1961.
I plan to remove the fuel gauge and slip a length of garden hose to the bottom, screw it onto my drill pump, and pull a sample into a glass container.
I wonder what I'll find? John Aldens socks?