Silly question about invites

We got our invites beginning of July and FMIL offered to mail them out for us.

Now I have a few leftovers and a few people i didnt send to. They have 61 cent stamps on them and the PO told FMIL it was fine with the 61 cents.

Do I need to go to the PO to mail them. Im kinda worried because I put one in the mail box near my house and it was going to Middle Village and she STILL hasnt gotten it. Prob stupid idea for me to throw it in there.

Do i have to go to PO directly to mail them out even if they dont need extra stamps?

Thanks!

All the 'extra' ones I had to send, I just put in the mailbox near my house and they all got where they were going. No idea why your friend still didn't get hers.

They just won't be hand-canceled, but I didn't really care about that at the point when I was sending out additional invites.

Thanks. Yeah I dont think FMIL hand cancelled them. whoops.

I also didnt number the RSVP cards....whoops again.

I had a couple extra ones. I stuck them in my mailbox, our mailman just takes our stuff when he delivers the days mail. Not sure if that's how it is everywhere or if our mailman is just extra nice!