Dispose of, part used, for lb50 (4)
I believe the answer is:
sell
'dispose of' is the definition.
(dispose of can mean to sell something)
'part used for lb50' is the wordplay.
I cannot really see how this works, but
'part' could be 'ell' (ell is a kind of part) and 'ell' is present in the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sell that I've seen before include "Retail" , "Betray" , "Decorative edging" , "Market, vend" , "Dispose of for money" .)