Utter garbage is garbage made by utters. Why the garbage is uttered remains an utter mystery, though a mutter regarding the utter has been guttered by a utterly muttering - not to mention fluttering - shoe prone to stuttering. Why? Tons of nose, certainly. It explains the smattering of fish engines thus powered.
Beware, for utter garbage can be accumulated in an utterly utmost, utmost utterly silly manner within garbage cans at the whim of an utter. Utter is Swedish for a sea-living mammal; they are no doubt responsible for every uttering of garbage. No wonder the sea smells fishy. Beware the garbage-can approach. Don't let it approach you, lest you be canned and garbage-filled.