What to do with someone else's mail that still comes to my house and looks important!?

If you receive some ones’ mails which look important, either you detour it to its original owner or send it back to the post office stating that that person does not lives there any more.

I just write “Return to Sender” on the letter and stick it back in the mailbox.

If it’s for someone nearby, I usually hand-deliver it. Otherwise, if I know the intended recipient’s address, I forward the items, and if I don’t know it, I put the items back in the mail with “Not at this address” written on them. I just hope that anyone who gets any of my mail by mistake does the same!

Yeah, I mean mostly for mail for people who used to live at our address but no longer live there. So I don’t know their forwarding address. I guess I’ll just drop it back in the mail!. thanks.

or… simply put it back in the mail box ( out box ) if you can’t mark it as “incorrect address”.