What to do with 50 Smartphones?

Hey Fam,
I have 50 Smartphones. Does anybody have ideas how to monetize this 50 phones?
I have tryed classic phone farming. Didnt payed off.

Region Europe.

Thanks for your advice

I guess there is not much to do with it, except using your phones as clients for some apps, that earn money via watching videos and stuff. Or you just try to sell them. I guess that would be the best way, just sell them and from the money earned, you could invest in something more profitable. Even if the phones are old, you probably get 20€ per Phone and that would be still 1000€ for all the phones.