Was he with organisation that supplies paint? (9)
I believe the answer is:
whitewash
'paint?' is the definition.
(I know that whitewash is a type of wash)
'was he with organisation' is the wordplay.
'organisation' is an anagram indicator.
'was'+'he'+'with'='washewith'
'washewith' is an anagram of 'WHITEWASH'.
'that supplies' acts as a link.
(Other definitions for whitewash that I've seen before include "Cover-up -- wall coating" , "Wall pigment; defeat" , "Attempt to conceal bad news" , "Used on walls to cover up a misdemeanour?" , "Lime solution; cover up" .)