Redesign menus with oil paint (8)
I believe the answer is:
emulsion
'paint' is the definition.
(I've seen this before)
'redesign menus with oil' is the wordplay.
'redesign' indicates anagramming the letters (I've seen 'redesigns' mean this).
'with' says to put letters next to each other.
'menus' after 'oil' is 'oilmenus'.
'oilmenus' anagrammed gives 'EMULSION'.
(Other definitions for emulsion that I've seen before include "Type of paint" , "Mixture of insoluble liquids" , "Wall paint" , "Mixture involving two liquids which do not readily combine" .)