If you've decided to hire the services of a medium, for whatever reasons, there are a few things you should keep in mind to guarantee you get the best session possible. First of all, try to come in with an open mind. You may be feeling skeptical, but if you let that be an issue, it can certainly color your results. A corollary to that is that it's important, to be honest about why you're there. If you're only trying to debunk things or to expose the medium as a fraud, go ahead and admit it up front. A medium who's legitimate will probably still be willing to work with you.
In September 1878 the British medium Charles Williams and his fellow-medium at the time, A. Rita, were detected in trickery at Amsterdam. During the séance a materialized spirit was seized and found to be Rita and a bottle of phosphorus oil, muslin and a false beard were found amongst the two mediums. In 1882 C. E. Wood was exposed in a séance in Peterborough. Her Indian spirit control "Pocka" was found to be the medium on her knees, covered in muslin.