a comedy of errors, based on poor planning, and very substantial lack of diligence, really becomes a point where you have to go "what next?"..
I don't think I would have stored a bare metal gas tank, in a sealed garbage bag, in some environment that would have the bag deteriorate within less than a year ; Like outdoors... (the local dumps say this stuff never rots..yeah, it does.. ), let alone not adding a couple bags $total 3$ of white rice to absorb moisture, and hung it inside somewhere.. and prevent rusting.. after stripping the tank to "bare", a 20 minute expense of time, and a $4 can of primer, would have prevented this all... I realize we are not all "wizards" when it comes to this stuff, but by the same token, it becomes hard to feel sorry for someone, when they really don't use good judgement.
I guess most of us that engage/do this for a hobby, take a few more precautions, as poor decisions result in major complaining from spouses.. and God knows, we NEVER want to hear that from them.... bt/dt/
sorry to hear about your misfortune, I think you may learn from the experience.. after you re-sand and re-prep the tank, again.....