On the old iPhones if you got lucky you could cut the power on it, pull the logic board out, and we’d stick it in an old jewelry vibrator filled with 99% rubbing alcohol. Hit it with a heat gun right away to disperse any liquid. Once dry id hook it up to a cheap screen and battery I knew was good before sticking it back in the phone, if that came on. Then work your way backwards replacing anything that needed to be replaced out of the other parts, or hook up to a docking cable to a computer to back up to iTunes, so they could get their data. Slowly apple forced everyone into iCloud backups, so the need dropped more and more for such though.
On the old iPhones if you got lucky you could cut the power on it, pull the logic board out, and we’d stick it in an old jewelry vibrator filled with 99% rubbing alcohol. Hit it with a heat gun right away to disperse any liquid. Once dry id hook it up to a cheap screen and battery I knew was good before sticking it back in the phone, if that came on. Then work your way backwards replacing anything that needed to be replaced out of the other parts, or hook up to a docking cable to a computer to back up to iTunes, so they could get their data. Slowly apple forced everyone into iCloud backups, so the need dropped more and more for such though.