Hi, I've got a Chinon CE-4s camera that works well except for one problem that's developed recently: The meter readings are sometimes unreliable. When set to aperture-priority automatic mode, I can point the camera at a subject and see, in the viewfinder, a reasonable shutter speed that the camera has selected. (Say, 1/125s for an outdoor scene at f/11 with ISO 100 film.) If I then adjust the aperture, the shutter speed may change in a reasonable way (say, to 1/60s if I close down the aperture a bit) or it may suddenly jump to the overexposure indication, even for a small change in aperture or in light that's dim enough that the camera shouldn't be showing overexposure for any aperture. This same problem occurs with any lens attached and with any settings on the ASA dial, so I know it's not a lens problem. Because of this problem, I haven't been using the camera much recently, but today I discovered that the problem temporarily goes away if I move the aperture ring rapidly back and forth a few times, or if I slide the aperture coupling ring in the camera body back and forth a few times with the lens removed. Thus, my hypothesis is that there's some corrosion or contamination in the aperture-coupling ring in the camera body. I was hoping somebody here would have some advice on how to deal with this. Would electronics cleaning fluid help? (The sort of thing that Radio Shack sells to help with old stereo tuning dials that produce static, for instance?) If so, where should I aim the spray and what precautions should I take? Would some other method of cleaning or adjustment be more appropriate? Thanks for any advice.