I just worked with some smart and excitable kids from Parts & Crafts and we managed to get a sample of suspected motor oil residue from a nearby street drain to fluoresce strongly enough to be detected (faintly) by a desktop spectrometry kit:
Exciting! See the red region just below 600 nanometers.
We did it by using one of the "psychedelic effects" caps for the green laser pointer, which makes crazy pattterns of laser light -- but importantly, it spread the beam of the laser out enough to create a lot more fluorescence. The signal is very faint, but definitely there.