Rinse off sticky stuff (5)
I believe the answer is:
resin
'sticky stuff' is the definition.
(sticky substance)
'rinse off' is the wordplay.
'off' is an anagram indicator.
'rinse' anagrammed gives 'RESIN'.
(Other definitions for resin that I've seen before include "Sap product" , "Substance produced from sap of some plants and trees" , "component of varnish" , "varnish, perhaps" , "stuff that's sticky" .)