I drained the tank, and the vinegar worked wonders! I didn't even need to use any objects to knock off any rust. Unfortunately, after I rinsed the tank a few times with water, and looked for a container and fuel for a final rinse, it flash rusted.
I read that it might do so, but in 10 minutes?
I'll have another overnight soak, and have my ducks lined up and see if I can prevent that from happening again.
Here are a few pics of what came out after a week long soak.