Waste product found in your earwax (4)
I believe the answer is:
urea
'waste product' is the definition.
(compound in urine)
'in your earwax' is the wordplay.
'in' indicates the answer is hidden within the clue.
'UREA' is hidden within 'your earwax'.
'found' is the link.
(Other definitions for urea that I've seen before include "Waste matter" , "Waste material" , "organic compound" , "It's produced by piddling" , "Compound found in urine, synthesised as a fertiliser" .)