Rinse off plastic component (5)
I believe the answer is:
resin
'plastic component' is the definition.
'resin' can be an answer for 'component' (I have seen 'component of varnish' mean 'resin' so perhaps 'component' could also mean 'resin'). I'm not sure about the 'plastic' bit.
'rinse off' is the wordplay.
'off' indicates anagramming the letters.
'rinse' is an anagram of 'RESIN'.
Can you help me to learn more?
(Other definitions for resin that I've seen before include "Elemi, for example" , "Sticky stuff for siren" , "Fiddler's need" , "hashish, say" , "Risen (anag.)" .)