Yellow polish (4)
I believe the answer is:
buff
I believe this is a double definition.
'yellow' is the first definition.
(thesaurus)
'polish' is the second definition.
(buffing is a kind of polishing)
(Other definitions for buff that I've seen before include "Yellowish colour - polish - expert" , "Yellowish brown" , "with attractively well-developed muscles" , "light shade" , "Polish; yellowish-beige" .)