We keep a lot of old field elements, some driver stations we made, various robot parts, and some other things related to robotics in a shipping container next to our fuel cell, similar to:
Some robots are stored in a little closet on the exterior of our school, and then we also have another closet behind our machine shop / computer lab / classroom where we keep the rest of the robots we still have, not all of which operate, but are still pretty assembled. I think we have pretty much all of them, though I'm sure some of the earlier ones are no longer there. The only robot to really see cannibalization was our 2004 robot, which remains our test robot for this year, and has been very modified in the last two years. These three areas are reffered to as super super secret store, super secret store, and secret storage.
The school used to give us a whole abandoned classroom to keep things, but due to expansion, they just gave us the shipping container.