Hi John, thank you for pointing me to the world of oscilloscope washing, cleaning.
I read about the experiences of others and the industry washing oscilloscopes with water. The hairs on my head used to stand up at the idea, but now I recognize that it is relatively safe, although it requires WORK.
I compare it with my long experience of "don't fix what is not broken", and the good luck I have with my old scope that had a 40 years leave of absence.
I perfectly cleaned the exterior of my 547, and it is shiny. The inside is different, with plenty of dust deposited on the tubes and surfaces. I like to preserve it like that for its dramatic effect. The instrument will be perfect for my grandchildren to play with it when they are a little bigger, and it may awaken their interest in electronics. I plan to show them the inside of the scope to be impressed with its age, but after that the inside will be off limits to them.
But... if I experience any failures, I feel competent enough to trace them to the failed component, or particles of dust, and I will remove just those offending particles.
NOTE: I have a different standard for washing myself, staying clean inside and changing my underwear, ha ha ha.