Has anyone successfully put their speakers in storage for an extended period of time?

So this is where i can share some insight into speaker storage, i Have three storage lockers with speakers in them and i have had these lockers for ten years, these are shipping containers that was on large ships 10' by 40' long, it seems that the foam does rot and this is a sealed container!
and another issue at hand is the glue that the manufacturer uses to build the cabinet breaks down over time and the cabinet rattles when played, but each speaker has it's own issues. so here we go, the Maggies- the panel glue for the construction fall's apart along with the voice coil, Jbl suffers from foam rot and it's white cones foam get's hard and cracks, 
Altec with treated pleated surrounds, the treatment flows to the bottom of the woofer, electrostats- the Mylar needs to be re-tighten, then their is the issue of wired connection building up resistance on the connections- and the screws get rusted from time to time  the oils in the verneer dries up.
 then you might start to have crossover componets draft out of spec but if you take care of the speaker for storage you should be fine.  

Yes!

I stored in the original boxes a pair of Spendor SP1 for well over a decade. I now use them in a second system and they are wonderful.  Still sound amazing.  No problems at all.  Wife draped the cartons in lovely fabric.  Topped with glass and left in a spare room looking like a table.
so glad I kept em’.

You should be able to do it. Just be sure the storage facility is "Climate Controlled", not the kind where the roll-up door is outside. I would check them annually for any disintegration of the surrounds.