Getting rid of cheap material (7)
I believe the answer is:
sacking
'material' is the definition.
(sacking is a kind of material)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for sacking that I've seen before include "Terminating someone's employment" , "devastating" , "Looting - coarse cloth - dismissal" , "P45" , "Firing the coarse cloth" .)