The short version of how to tell if Ouija is nonsense is this:
Blind fold the sitters (watch in amazement as the messages turn into gibberish) Personally I think blaming it on the ideomotor effect accounts for around 1% of cases, the rest are folk conciously moving the planchete.
What did OI have to say
Ouija board If there really is an afterlife, I'll bet the best way to contact it is through a plastic, mass-produced board game from Milton Bradley! --Mad Magazine A Ouija board is commonly used in divination and spiritualism, often by friends out to have some fun. Sometimes, users become convinced they've been contacted by the spirit world. The board usually has the letters of the alphabet inscribed on it, along with words such as 'yes,' 'no,' 'good-bye,' and 'maybe.' A planchette, a small 3-legged device with a hole in the middle or a pointer of some sort, is manipulated by those using the board. However, users often feel the planchette is moving of its own accord rather than responding to their own unconscious muscle movements (ideomotor action).
The users ask a "spirit" a question and the pointer slides until it stops over "yes" or "no" or a letter on the board. Sometimes, the selections "spell out" an answer to a question asked. Some users believe that paranormal or supernatural forces are at work in spelling out Ouija board answers. Skeptics believe that those using the board either consciously or unconsciously move the pointer to what is selected. To prove this, simply try it blindfolded some time Have an unbiased bystander take notes on what words or letters are selected. Usually, the results will be unintelligible. The movement of the planchette is not due to spirits but to unconscious movements by those controlling the pointer. The same kind of unconscious movement is at work in such things as dowsing and facilitated communication.
Before there were Ouija boards in America there were talking boards. These could be used to contact the spirit world by anybody in the privacy of one's own home; no séance was required and no medium need be present (or paid!). No experience necessary! No waiting! Quick results, guaranteed! The Ouija board was first introduced to the American public in 1890 as a parlor game sold in novelty shops. E.C. Reiche, Elijah Bond, and Charles Kennard ... created an all new alphanumeric design. They spread the letters of the alphabet in twin arcs across the middle of the board. Below the letters were the numbers one to ten. In the corners were "YES" and "NO." Kennard called the new board Ouija (pronounced 'wE-ja) after the Egyptian word for good luck. Ouija is not really Egyptian for good luck, but since the board reportedly told him it was during a session, the name stuck.* Kennard lost his company and it was taken over by his former foreman, William Fuld, in 1892.
One of William Fuld's first public relations gimmicks, as master of his new company, was to reinvent the history of the Ouija board. He said that he himself had invented the board and that the name Ouija was a fusion of the French word "oui" for yes, and the German "ja" for yes.* Although Ouija boards are usually sold in the novelty or game section of stores, many people swear that there is something occult about them. For example, Susy Smith in Confessions of a Psychic (1971) claims that using a Ouija board caused her to become mentally disturbed. In Thirty Years Among the Dead (1924), American psychiatrist Dr. Carl Wickland claims that using the Ouija board "resulted in such wild insanity that commitment to asylums was necessitated." Is this what happens when amateurs try to dabble in the occult? Maybe, if they are suggestible, not very skeptical, and a bit disturbed to begin with. However, even very intelligent people who have not gone insane are impressed by Ouija board sessions.
They find it difficult to explain the "communication" as the ideomotor effect reflecting unconscious thoughts. One reason they find such an explanation difficult to accept is that the "communications" are sometimes very vile and unpleasant. It is more psychologically pleasing to attribute vile pronouncements to evil spirits than to admit that one among you is harboring vile thoughts. Also, some of the "communications" express fears rather than wishes, such as the fear of death, and such notions can have a very visible and significant effect on some people. Observing powerful messages and the powerful effect of messages on impressionable people can be impressive. Yet, as experiences with facilitated communication have shown, decent people often harbor indecent thoughts of which they are unaware. The fact that a person takes a "communication" seriously enough to have it significantly interfere with the enjoyment of life might be a sufficient reason for avoiding the Ouija board, but it is hardly a sufficient reason for concluding that the messages issue from anything but our own minds.