Bottle top in waste container (3)
I believe the answer is:
bin
'waste container' is the definition.
(rubbish bin)
'bottle top in' is the wordplay.
'top' suggests taking the first letters (in a down clue, the first letter is top).
The initial letter of 'bottle' is 'b'.
'b'+'in'='BIN'
(Other definitions for bin that I've seen before include "wine storage facility" , "Litter container" , "Where to put rubbish" , "Ordinary household receptacle for rubbish" , "Discard" .)