Possible Clues:

• How an S.C. comes in the fore in a medium sort of way (6).
• It might be one's forte to get a score with such painting
• Painting fresh coat, hence removing lid
• Almost new business may be going to the wall
• Picture painted on wall or ceiling before plaster is dry
• Painting style
• Just picture how it was made afresh
• Mural on wet plaster
• Watercolour done on wet plaster
• Painting done in wet plaster