For an idea you could create a trash can and then place some trash inside.
Great job anyways 
This model is trash.
It disgusts me to look at it.
Ok, seriously now, it looks pretty good.
Looks trashy. In a good way! Looks so disgusting. . . . I don’t know how to make it sound like I’m complimenting you, because your art is REALLY trashy. But it looks trashy good? sigh I mean looks like really good though.
In trash world, this is the most beautiful trash :-D?
Yes indeed lol! Don’t know how to say how trashy this looks without making it sound bad 
This model is garbage.
Haha, just kidding. On a more serious note it could use more advanced texturing.
i don’t know what really to add here, making trash is hard.
Dumpster bags could work plenty.
I believe I put texturing, and not adding more things.