Throw away at the tip (4)
I believe the answer is:
dump
This clue is a double definition.
'throw away' is the first definition.
(I know that dump is a kind of the throw away)
'the tip' is the second definition.
(I've seen this before)
'at' acts as a link.
(Other definitions for dump that I've seen before include "number two" , "waste ground?" , "deposit" , "Jettison; (rubbish) tip" , "Place for unwanted things" .)