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' indicates putting letters inside (inviting in, as for dinner).
'discontented' means to remove the middle letters (the word's contents are removed).
'artists' with its centre removed is 'as'.
'ere' going around 'as' is 'ERASE'.
(Other definitions for erase that I've seen before include "Efface" , "Scratch" , "Remove permanently" , "To remove all trace" , "Blank out" .)