Paints ruined silo (4)
I believe the answer is:
oils
'paints' is the definition.
(oil is a kind of paint)
'ruined silo' is the wordplay.
'ruined' is an anagram indicator.
'silo' is an anagram of 'OILS'.
(Other definitions for oils that I've seen before include "paintings?" , "Reduces friction" , "Soil, oddly, used by painters" , "landscapes, perhaps" , "art exhibits perhaps" .)