So then...once they become depleted is there anything that can be done with them?

I have quite a number just hanging around various depots doing nothing much. I can't use them to build new depots in their depleted condition, and I would think that without man power their supply potential wouldn't be worth taking them along in a stack. I was thinking about sending them into the desert to completely exhaust and vanish (if they will do so like troops units do) or maybe even sending them back for the doodlers to recapture, so they can whip them back into shape...then I can re-recapture them again. Possible???
