Green’s Dictionary of Slang

(US) dirty, messy, unappetizing, unappealing.

1986		Stinson & Carabatsos Heartbreak 152: What a pathetic, grunged-out little whorehouse [HDAS].
1999		Guardian Rev. 5 Nov. 23: Some grunged-out, narco-terrorist had spiked the water supply with acid.
2004		D.E. Donche Jr Locker 6t3 107: This new entity was all grunged out.