Another of Doc Greene's inventions, Spectral Vapor Filters are intended to capture ghosts in some sort of energy field and hold them indefinitely. Unfortunately the lack of any actual ghosts means that these potentially dangerous devices have never been tested. Frankie Greene keeps one in her sock drawer.
When Frankie spotted a news report by Huxley Prescott on a ghost sighting, she immediately thought that it would be a perfect time to test the Spectral Vapor Filters. She gave one to Cody Burns to use, and he passed it on to Charlie Burns when there was a call out to investigate a ghost at the bank. Soon there was a full-on ghost infestation of the town, and out of desperation, Graham Burns attempted to use the Filter on a ghost. It appeared to work, but moments later the Spectral Vapor Filter spat the ghost back out. Later Frankie, Cody and Doc Greene were confronted by another specter at the Hall of Inspiration and used a Filter on it, achieving similar results. When the "ghost" turned out to be the hologram of Chester A. Arthur, they realized that the other ghosts were probably just holograms too.
- The Spectral Vapor Filters owe just a little bit to the ghost traps used in Ghostbusters.