Bore cleaning question

[gunsrfun1]

Hello - I have read a lot of the posts on Luger cleaning, but I also recently read a post mentioning that the metal in Lugers is softer than today's gun metals. (That particular post was in reference to a bolt that chipped upon firing.) This got me to wondering if it's OK to use a standard bronze bore brush in a Luger barrel. Is there any danger of harming the barrel with these brushes (assuming of course they are used with a solvent, such as Hoppes.) I wouldn't think so, but thought I would ask before I do it. Also -- does cleaning the bore on an "original" (vs. reblued) gun devalue it in any way? Thanks