I will admit when I am wrong. It looks like that method would work. I have been around the computer building community for 20 years, and I have never even heard someone even mention that method.
However, I wouldn't have the patience for that when a cloth and a little alcohol works so well, is so cheap, and gets the job done quickly every time.
Different strokes for different folks, I guess.
Not to dis the OP for his tape method. Nor do I care to question the idea that some type of tape doesn't leave an adhesive residue.
But even if I followed the "tape method," I'd still clean off the processor cap with isopropanol. And while we'd want to have 99% isopropyl handy all the time, second-best is 70% drugstore rubbing alcohol.
TIM of various kinds often leaves an oil stain on the processor cap, or you can see it if the cap has been lapped to bare copper, used with an oil-based TIM, and examined some time later.
The only thing that will thoroughly clean the surface is a good solvent, and the only good solvent for this task and the cleaning of various other electronic parts is isopropyl alcohol.