Save weathered paint. Isn't that the best thing there is? especially now that you can buy cleaning machines for small change from all kinds of budget providers such as Lidl and Action. Those cleaning machines may not be as serious bastards as a professional uses.
But they can destroy more than you like if they are used improperly.
Cleaning is a job that requires patience first. The cleaning paste must do the work. If a great deal of pressure is exerted on the cleaning machine, frictional heat is created between the cleaning disc and the paint.
And that can definitely kill the paint that you thought you were cleaning.