Answer: scumbles

AnswerCrossword Clue
scumblessoften the lines or colors of (a drawing) by rubbing lightly
scumblesapply (a color) in this manner
scumblesSCUMBLE, to soften the outlines by rubbing lightly
scumblesto make (as color or a painting) less brilliant by covering with a thin coat of opaque or semiopaque color applied with a nearly dry brush