I thought about having Cassie leave something much worse, but I figured the show would edit that scene out entirely, negating the result.
[Rose Bowl Self Storage, Pasadena; the pair have just returned from another "plant" from the same episode] (PW) "Okay, so the old gas pump is now in Darrell's unit, let's see what happens with it..." (Dave Hester, Newport Consignment Gallery, using a flashlight to peek into the locker) "There's maybe some valuable stuff here... Wait a minute... (seeing the pump in the back of the unit) That looks like an antique gas pump in perfect shape... this one's DEFINITELY mine!" (PW) "...And now it's Dave's locker!' (CW) "Crap... I knew I should've hidden that thing better! (turning and flipping open the time machine) Well, I've got something else up my sleeve..." [FZZZT FZZZT] (PW) "So did you do something with the gas pump?" (CW) "No, but I did leave something else in that storage unit..." (DH, on the iPad) "What's in this drawer... Aw [BEEEP] it's a DEAD SKUNK!" (CW, the smell already wafting from her) "Yyyyeah... I'm so gonna need a shower after that." (PW, holding his nose) "You dink?