A way I repurpose an old Android.
1. Wipe to factory settings.
2. Reconfigure all device settings offline.
3. Use public wifi to access F-Droid repository.
4. Download a dumb amount of F-Droid apps.
5. Take device offline.
6. Reset wifi settings.
7. Disable certificate authorities.
8. Set wrong date.
The last 2 make it harder for unwanted remote connections, excluding bluetooth and n.f.c..
To go back online, fix time and turn on certificate authorities.
