After Edna and Citizen Brown leave the Decycling Chamber, you can spend some time looking around at the stuff stored there. Just don't free Einstein until you get this trophy.
The items you need to examine are:
BB Guns (far left middle shelf)
Sexy magazines
License plates
Arcade machine (in a cage)
Gag supplies
Vinyl records (far right behind counter)
Skateboards (far right next to a wire cage)
Beer
Cigars
Pinball parts
The trophy should pop right after the last of the items is examined.
Have fun!