I had this very same issue once. What I did was I grabbed some buckets, bought a brand new dish brush at the dollar general for like 2 bucks, turned on a CD and went to town scrubbing stuff. I removed as much crap as I could, did a WC in the process left the lights off and sucked up as much of that junk as I could. Left the light off for a few days and repeated the whole thing again after the black out, good ol' elbow grease works like a charm every time.