Sell them quick enough before the market is flooded with newer and better GPUS that ultimately put yours into no purpose
My estimated time of Bitcoins dieing (lets say?) the year: 2020. Don't ask why I think the year 2020. I'm just speculating.
(I hope that doesn't happen) but your GPUS will be no good in 2020.
Let's say Bitcoin (and all alts) goes to zero because Nakamoto was wrong

. What could I do with 50 GPUs besides selling them, have fun with my kids (and the whole school) or replace my home heater with them?
Any ideas that have been implemented? Like starting a "gaming center" or process proteins...