|I'm not sure I understand 'dirty' abstract, even after reading the challenge description. I am sure that it doesn't matter to me.
I have chosen my five favourite entries and have given each of them a score of 10. This is one of the five. And all five get the same comment, because what I can say about any of them applies equally to all of them.
These are the relevant definitions that I like (today):
Abstract. Existing conceptually but not physically.
Abstract Art. Graphic poetry in which a sophisticated idea is communicated without saying it out loud.
This photograph qualifies as abstract art.
One the one hand, it's not merely a negligently rendered version of reality, which is what blurry photographs are: that's not abstract art.
On the other hand, it's not patently meaningless, which is what random colour blobs and swirls are: that's not abstract art.
On the third hand (you see how difficult abstract art is ... you need three hands to even hope to juggle it), It clearly suggests something, refers to something, means something, goes somewhere; but it intentionally withholds the key and leaves the beholder to get down on his-or-her knees and pick the lock: that is abstract art.
And the really good ones, like this one, have more than one possible lock, that opens more than one possible door.
So, 10 for you, and the Order of the Thumb, and my thank you.