Cleaning Onan generator slip rings

I've used Flight Systems Slip Stick on several different generators over the years with good results. I've never needed to drop the generator to use it. I do run the voltage/resistance checks in the Onan service manuals first though, to see if cleaning is needed. Generally, I've cleaned the slip rings on generators that have sat for extended periods without running. The most recent one I worked on had sat for about 4 years and the rings were pretty black.

Here's a video on using one:

Using the Slip Stick