Share 'Cocoa cake pulverizer?'

I'm accumulating a LOT of cocoa cake and have not been able to find anyone local that is willing to pulverize it. Any suggestions for an inexpensive solution? I easily have 400 lbs of cake and a lot of demand for the cocoa powder!At the moment we're pulverizing small amounts with a food processor and varying size sieves but it's ridiculously time consuming.   Ideally the solution would be under $…