As far as what you can reach (with the machine turned off), the biggest danger is dislocating a shoulder due to the contortions you have to perform to get back there. It’s a pain, but with determination and patience it’s not beyond your ability
That cleaner will evaporate quickly (fumes), but if you are vented outside you shouldn’t have to move the machine.
I had that exact problem. It was very strange, fine that evening but when I turned it on the next day there was this terrible vibration.
In a situation of a build-up deposit, it is subtle and progressive but this was a sudden change. I still haven’t figured that one out yet. I was quite sure the fan bearing was bad so I pulled the fan out and cleaned it. After cleaning the fan the bearing still felt tight so I reinstalled it and the machine was normal.
Get that fan clean and you’ll be back on your wheels.