Wouldn't the spirits be from wherever you use it? Like, in grade 7 me and my friends used in in Jarrett's basement and the spirit that moved it must have died nearby.
I'm not sure what my favourite part of those lazy ouija board afternoons were - subtly moving my blindfold so I could still see just enough to spell out creepy words to freak out my gullible friends, or else having two of them wear blindfolds "to prevent cheating" then delicately reaching over and moving the slider thing myself while pretending to read out the letters. Sure they mad the next day when they figured it out, but it wasn't *me* who told them to tell everyone they knew that ghosts were real. The spirit of the dead settler told them to.