Originally Posted by
CWAL
If you're smart enough to write on the back of the MOs when you mobile deposit them, you won't have this problem.

I don't want to write on the MO after mobile-depositing it, in case the deposit is rejected and I need to deposit it somewhere else (though, so far this hasn't happened to me; and you could probably write something that won't prevent future deposits... just not "ALREADY DEPOSITED").
But it's easy enough to put the MO in a separate pile after depositing it. I put them in the same place that I put receipts that I'm saving.