1/2" tape cleaners?

Does anyone know anything about 1/2" tape cleaners? I remember (I think) seeing a device in the tape library of the giant insurance company I once worked for. This device, if I remember correctly looked like an audio open reel tape deck but would take a 1/2" (9-track style) tape reel on one side and had a take-up reel on the other. If I remember correctly the tape passed over a "spinning wheel" which had slots in it. I think this wheel would "clean" the tape. It's all a bit hazy now, but I think this device was used to clean and re-tention 9-track 1/2" tapes. (the # of tracks does not matter, but I say that to give the proper context). Anyone know of these, have one, know of one, or if they work and are safe? I have some (well, many) 9-track tapes which were stored in a very poor (read humid) environment. The look like they have mildew on them. I'd like to try cleaning and re-tensioning one and, after baking, see if it will read. Seems like one of these devices would come in handy. Any experience? -brad