Recently bought an original Boyt '42 M1928 Haversack for reenactment use.

 

Haversack itself is in decent condition, but I've noticed a few stains on the pack. They look like rust stains, but not quite sure. A bit of research also reveals that some haversacks had brass-type buckles and clips. I know brass doesn't rust, but I'm still wanting to learn how to clean and maintain them (if possible). In addition to cleaning those aforementioned stains.

 

I've done a bit of google research already, but with so many opinions out there I'd like to narrow down some solutions directly from the reenactment community.

Any help would be appreciated.

Nice pickup! The stains you posted and the oxidation on the meat can pouch are totally normal and with use the Oxidization will wear off. If your using this for reenacting g your in good shape. Your pack doesn’t need to be sparkly clean. The rust stains and stains I. General I the fabric will be extremely hard to get out as they’ve had A LONG time to set in there. So there’s likely not much you can do.

Those are very minor issues - the type that often existed when these were issued. You could use a dry soft toothbrush very lightly on the steel bits but frankly, with 50 years of collecting and archival training, you are best to just leave it alone. in 99% of cases attempts to hide or 'fix' normal wear, age, stains, and use wind up turning into the dreaded "I-see-you-tried-to-repair-it" look.  Most collectors/historians etc. would rather see an issue normal for its age than a blatantly modern intrusion left by an amateurs recent fix-it attempt. 

If you are going to use it for reenacting, don't worry about cleaning.  It's collectibility will be ruined in short order any way.