I found a site on the web that showed how to take the top off of the camera (not hard). The main problem is getting the rewind nob off. Once you see how it is done, it isn't difficult at all.
Then I cleaned the rangefinder parts with a q-tip and some alcohol.
Of course, I had 2 Canonets at the time, so I could risk one. It did work well enough that I was able to do the second.
I never worried about the light seals. Never had a light leak. Then the back started opening on its own. $6 on eBay and I had a seal kit. No more problems there either.
I would try to find something softer than the Q-tip, but it worked great.