Possible Clues:

• Decorative coatings
• Puts on at least one coat
• Art classroom supply
• Puts on a coat outside that is not inside
• How one puts on the outside what is not in the postscript
• On the surface they are not to be found in the postscript
• What is not in the postscript is for the artist
• In the postscript it is not a matter of coats to put on
• What you have a brush with are not in the postscript
• Makes picture with canvas and oils