You have to take the amp/chassis out of the shell, remove all of the tone knobs, switches, input jack, channel selector buttons, The LEDs that are mounted to the back of the face plate ect.
the tone controls, switches, channel selector buttons, and input jack, are all connected to separate PC boards which then connect to the main boards, You have to be very care full they are not the most robust.
Once you get the face plate off you spray it down with a product called (Groove Juice) it's a symbol cleaner, it's what I used it works excellent. Let the groove juice sit on the face plate for about 1 minute (make sure to evenly disperse the groove juice) spray off with water, dry it and put her back together.
Keep in mind that it is a little bit evolved and can be dangerous to do if your not care full, if your not experienced at working on amps, I would advise you not to do it your self.
