Would anyone agree that "licked" can be considered a modifier of "clean"? reason? well, how was it cleaned ? it was "licked" cleaned. So there is a "how" element in the quesion. If so, any problem qualifying it as an adverb. I know this probably draws some oppositions.
Well, I have no doubt at all that past participles can be used as adjectives. That being said, I am also in the camp of people who also see this usage passive. "Licked clean by the dog"? - sure it's a participle used passively. Now, back to my earlier question, any thoughts?