Material to exploit after initial downsizing (4)
I believe the answer is:
silk
'material' is the definition.
(silk is a kind of material)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for silk that I've seen before include "Senior lawyer; type of worm" , "Barman" , "Fabric obtained from the cocoon of a worm" , "Riding hat covering" , "Lustrous fibre" .)