On types of alcohal, would it really matter? I'm planning on whipping up a batch of MAP myself. I am curious about Peroxide though. I've seen it stated on a differant forum that it can ruin the finish on a gun if left on too long.How long is too long? Also isnt peroxide a petroleum thing? A shame when you almost need to be a chemist to enjoy a simple hobby.
Unburned Pyrodex won't harm anything it's left on.
Pyrodex fouling draws moisture out of the air and between the moisture and the acids that form in the fouling it will not only remove the finish but it will cause the underlying steel to form deep rusty pitting.
Real black powder fouling will do the same thing. That's why it's important to thoroughly clean a black powder gun as soon as possible after it has been fired.
Pyrodex is not a petroleum product if that is your question.
As far as "petroleum things" go, Pyrodex fouling and black powder fouling will form a hard material that is more difficult to remove than the fouling left in the bore if no petroleum is present when the powder burned.
By "present" I mean, a wet, oily coating, which is not the same thing as a surface that has been oiled and then wiped with a clean rag.
An oiled surface that has been "wiped clean" won't leave any unusual "hard fouling". That's why I suggest that you quit dwelling on this "petroleum" issue.
Unless there is a wet coating of oil on the surface, there is nothing to worry about. If it is "wet", wipe it clean and forget about it.
When I say, "Wet" I'm talking about enough oil present that rubbing it with your finger will leave a noticeable coat of oil on your finger.