The vibraphone is one of the most complex instruments in the percussion family due to its many moving parts to make it all work. Unfortunately, the pedal and damper mechanisms are not universal from brand to brand so you will need to give these instruments a more thorough inspection. A majority of the time issues on vibraphones are from the pedal or the damper. Beyond the basic keyboard cleaning tips mentioned you can check for the following issues: Bar Cleaning: Since the vibes have metal bars cleaning them with a dry cloth first and then denatured alcohol or a multi surface cleaner such as Pledge will help remove the built up dirt and grime.