Channels bleeding into each other

Hi, tried to research this but apparently was not asking the correct question. I have a Yamaha CR820 whose channels seen to be bleeding into the other. When I turn a channel to 0 to mute that channel sound from the other  channel seems to come through. Simple cleaning required or sound like a more serious problem? Any insights would be greatly appreciated. Thanks, Dave.
Technical term is "crosstalk." 

Turning the balance all the way to the left or right is not how to tell. :) The balance control is not meant to go all the way to off, but to give you a range of adjustment for recordings, hearing, and situations when equal loudness is not ideal. 

Crosstalk is usually very difficult to avoid it completely in stereo components. Even very good stereo components will not be perfectly free of crosstalk, and when measured may be -60 to -90 dB. 


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