Peace be upon you and God's mercy and blessings.
Grand Ayatollah Sayyid Khamenei (may God protect him):
Simply leaving the devices does not permit you to dispose of them. You must return them to their owners if possible. If you despair of being able to identify or reach them, you should donate them to the poor on behalf of their owners, with the permission of the religious authority, as a precaution.
Grand Ayatollah Sayyid Sistani (may God protect him):
If you despair of reaching the owner, you should donate them to religiously observant poor people after taking a fee for any repairs you made. For owners you can contact, you must agree with them either to sell the devices and collect your fee or for them to come and retrieve them.
May you be successful in all good.