Antifreeze jug, a gallon of denatured alcohol, and enough fluorescein dye to make it look right.
Oil bottles full of Karo syrup.
ATF bottles full of acetone, with a little red food coloring.
If you can be sure the cops won't see it first, a counterfeit $50 bill "dropped" on the floor. Just good enough to pass the typical idiot, but be caught immediately by anybody who handles cash all day.