Crossword Puzzle Post box opening

Clue: Post box opening

Post-office opening (SLOT with 4 letters)
Openings at the post office (SLOTS with 5 letters)
Poster heading accompanied by a picture of a boxer, perhaps (LOSTDOG with 7 letters)
"Greetings ___..." (postcard opening) (FROM with 4 letters)
Post boxes' contents (CEREALS with 7 letters)
Post boxes? (CEREALS with 7 letters)
Post-office delivery (KISS with 4 letters)
Contents of some music boxes (AUDIOTAPE with 9 letters)
SFO posting (e.g. ARR with 3 letters)
Postwar Italian leader (DEGASPERI with 9 letters)