I recondition vintage drums, primariy Ludwig's, and have used gallons of Flitz on all types of surfaces over the years.
Be aware that the paste version, which comes in either cans or tubes is the full strength stuff and the liquid version is diluted down. While I do use the paste for certain items the bulk of my work is done with the liquid Flitz since it's easier to control. The paste tends to get squished into nooks & crannies where I don't want it to go and makes removal more difficult.
One other thing, the paste is supposed to protect similar to a wax and since I apply wax after Flitzing I usually will run the liquid version over the parts that I used the paste on just to remove the protective residue left from the paste.
Flitz is kind of funny in that it takes about 30 to 40 seconds before things start happening, why that is I don't know.
Maybe some sort of chemical reaction?
If working tough oxidation, staining etc. I've found that the bulk of your results are generated when removing the polish and not while actually working it on the part. When up against the "tough stuff" I make sure to get the Flitz doing it's thing by getting it on the areas I am working as soon as possible to get that 30-40 second window going, at least on the first pass, then repeatedly removing & re-applying as needed.
The key thing here is to work under good lighting conditions and pay attention to what's actually happening, which is why I never use mechanical polishing tools. Things can get away from you very fast when you add friction generated heat to the equasion......
If you have any doubts you should use the liquid version and always, and I mean always, never overwork your surfaces. I've seen lot's of damage done by people who thought they were improving on their work by continuing to polish when they had actually moved into the damaging phase. Sometimes less is better.......
Since I already had these photos hosted here is what even the liquid version can do by hand.
Early 70's Ludwig double tom stand base after washing, prior to Flitz.
After being Flitzed, re-washed & waxed........