Sent to collect ten-cent deposit (8)
I believe the answer is:
sediment
'deposit' is the definition.
(synonyms)
'sent to collect ten-cent' is the wordplay.
'to collect' indicates putting letters inside (inserted letters are collected by others).
'ten cent' becomes 'dime' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'sent' enclosing 'dime' is 'SEDIMENT'.
Can you help me to learn more?
(Other definitions for sediment that I've seen before include "Dregs; deposit" , "Particles that settle on the bottom of river or wine" , "Matter settling out in liquid" , "Stuff that settles to the bottom" , "End times (anag)" .)