Murmurs of discontent as empty garages get filled with booze and jewellery (10)

'murmurs of discontent' is the definition.

'empty garages get filled with booze and jewellery' is the wordplay.
'empty' suggests removing the centre.
'get filled with' is an insertion indicator.
'booze' becomes 'rum' (rum is a kind of booze).
'and' says to put letters next to each other.
'jewellery' becomes 'bling' (I've seen this before).
'garages' with its middle taken out is 'gs'.
'rum'+'bling'='rumbling'
'gs' placed around 'rumbling' is 'GRUMBLINGS'.

'as' acts as a link.