Wipe clean before entertaining discontented artists (5)
I believe the answer is:
erase
'wipe clean' is the definition.
(I've seen this in another clue)
'before entertaining discontented artists' is the wordplay.
'before' becomes 'ere' (poetic term for 'before').
'entertaining' means one lot of letters goes inside another (inviting in, as for dinner).
'discontented' suggests removing the centre (the word's contents are removed).
'artists' with its centre taken out is 'as'.
'ere' enclosing 'as' is 'ERASE'.
(Other definitions for erase that I've seen before include "Efface" , "Scratch" , "Remove permanently" , "To remove all trace" , "Blank out" .)