I have done this. I do not have photos but I will do my best to explain the switch and how to clean it.
Firstly, I will assume that we are talking about the same switch:
http://i257.photobucket.com/albums/hh238/sjeproductions/2061284929.jpg
Okay, so to open the switch, one must drill out the hollow rivets on either side. Before drilling, be sure the tape the switch shut because it is spring-loaded and you don't want to lose all the parts (I lost all the parts, wasn't fun). After the switch is open, the cleaning adjusting process is fairly simple. What your issue is with the kill switch is probably the little metal tab (momentary contact switch) has bent backwards over time and won't allow for good contact when the button is pressed. To correct this, simply bend the tab outwards to allow for a more positive contact.
Clean all the ball, spring, and little triangular plate. Carefully fit it back together (with somebody's help likely) and place some super-glue around the edge of the switch to replace the drilled-out rivets. Once you screw it back on the handlebars, the glue won't really matter.
Contents (if I remember correctly):
-Upper piece (plastic housing)
-Lower piece (plastic housing)
-Kill button (same as horn button, only red/black)
-Horn button (same as kill button, only blue)
-Light rocker button
-Two bearing balls
-Two springs (for the bearing balls)
-Metallic triangle piece
Okay so now a
step by step:
-Unscrew switch from handlebars
-Tape the switch unit closed to prevent it from springing open when the rivets are removed
-At all time work over a catch-container to prevent the loss of any parts that may fly away (a bin or box under the switch will work well)
-Carefully drill out the rivets being careful not to bite into the plastic body of the unit
-Once both rivets have been drilled, remove the tape while maintaining pressure on the unit to prevent the two halves from separating
-While holding the unit level with the floor, Slowly allow the two halves to open (they are spring loaded)
-CAREFULLY STUDY THE CONTENTS to ensure you know where everything came from and how it needs to go back
-Note the orientation of the Kill and Horn buttons (they are uni-directional)
-Note the location of the springs and associated bearing balls
-Note the orientation of the metallic triangular plate (uni-directional)
-Once you fell comfortable with the internal layout, fully disassemble the parts being sure that nothing flies away and becomes lost (spring loaded)
-Spray down all the important parts with contact cleaner / brake cleaner. Use sand paper to remove excess corrosion if present.
-Bend the kill/horn tabs outwards as needed to ensure good contact / functionality.
-Reassemble the unit (swear, lose some parts, hurt your finger, pause, drink a beer, curse some more, find your kid/wife/husband/neighbour for assistance, get them to help hold the damned unit while reassembling, curse at them, they caused this whole mess, drink another beer)
-Once you finally get the horrible switch reassembled, apply some superglue to the outer case to hold the upper and lower halves together (be sure not to get glue on any moving / contacting parts)
-Hold the switch halves together till the glue cures
-Screw the unit on the bike
-Ask your helper, "did you hear that!?", and look frightened. *pretend to be listening for something menacing nearby*
-Press the horn button. This will scare them.
-Profit.
