I once had a long stopover in Aukland Airport where a very expensive anti wrinkle cream was being promoted. As it was free I liberally spread it on. Checking an hour later I could see no improvement so more went on. I applied it about three or four times in total with no visible difference (to my mind).
On arriving at LAX I was escorted from passport control to a holding secure room for interrogation. Apparently there was suspicion that I had attempted to evade identification. They had difficulty getting my fingerprints.
I was so jet lagged my brain took a while to remember the anti wrinkle cream. I was escorted to the rest room and had to scrub my hands in very hot water, twice.
Eventually my fingerprints were uncovered and matched my records so I was released.
Clearly that product worked on the Polyfilla principal. 🙄