SOLUTION 6

In order to solve the junk puzzle, you need to ignore the items without letters on them and focus on what the 16 lettered items are. If you put them in alphabetical order by the name of the actual item, you will find that the letters on the items spell out the clue to the answer:
S balloon
O button
U cork
N crayon
D die
O dime
F envelope
L eraser
I jar
G key
H nail
T pill
N quarter
I straw
N tack
G washer

"Sound of lightning" should give you the answer: THUNDER.

We changed the puzzle order around at the last minute, moving this puzzle from #3 to #6, hoping that later in the game the teams would be more spread out and nobody would have to wait to try the puzzle (we only had five copies built). As it turned out, teams were very spread out at #3 and bunched up at #6, so we should have left them alone.

Among the useless items in the jar were: a corner piece from a Rubik's Cube, toy guns from a Stikfas figure, and $100 in game money from PQ2. I used my spare house key in one of the jars, and then accidentally left the jars behind at the final location. Luckily, they were still there the next day.