I haven't done any longevity tests. I've been too worried about spontaneous combustion to leave mine in the towers.
Seal the towers when not in use. You have to have air to have spontaneous combustion.
I understand that oxidation will only release what hydrogen is available in the vessel and without the introduction of air, the reaction will halt. My worry is that with the cellulose saturated with water and biodiesel, there may be sufficient hydrogen and oxygen available that under the right(hot and fuel) conditions, the unexpected could happen. Probably unwarranted, but I prefer to expect the unexpected.
mathematical elegance -- desired result achieved with minimal complication