As for cleaning, you can open it and have access to contacts and clean/file them as required. Look here: https://www.sl113.org/forums/index.php?topic=29178.msg210963;topicseen#msg210963
Some of the Members decided to install a relay to operate the 3 position solenoid to limit the amperage that is going through switch and adversely affecting its points.
A few years ago, I finally discovered the problem I had with the throttle switch failing after only few months after cleaning. This was a new switch from Mercedes. I had also thought the amount of amperage passing through was too much for the points to handle over time. I installed a relay and the switch worked longer than before, but still eventually failed. After much angst and several cleanings, I discovered the rivet that secures one side of the points and completes a connection a terminal, was not installed tight enough and lost continuity at that point. After peening the rivet and tightening the connection, I never had a problem again. I even removed the relay set up and the switch is still running strong years later.
I imagine original switches were probably made to higher standard and may not have the rivet issue. But if you have a newer switch and having durability problems, check out the rivet.
