Is using clothes without their owners' knowledge and then returning them without informing them a sin that necessitates financial rights, or is returning them sufficient? And is it obligatory to inform their owners of that, or is it enough to supplicate for them and give charity on their behalf to avoid problems?

It is impermissible for a Muslim to benefit from another's property except with their willing consent, for the Messenger of Allah, peace and blessings be upon him, said: "Indeed, the property of a person is not lawful [for another] except with his willing consent."

Therefore, a Muslim must repent, seek forgiveness, and ask for pardon from those they have wronged. Forgiveness can be sought generally without mentioning the specific transgression to avoid harm.

The value of what was diminished or damaged from objects, or their rental fee if they are rentable, must be paid. This is based on the consensus of scholars that whoever destroys, consumes, or takes something is liable for its value or its equivalent. However, if the objects are returned in their original condition and were not rentable, then there is nothing upon the transgressor other than repentance.