Unfortunately, one of my neighbors lost his father. The gentleman was 81, and a hunter and reloader.
My neighbor gave me a Samsonite travel/bowling ball bag stuffed to the gills with 30-06 brass.
He stored some of it in old Remington boxes, but most was loose or in plastic Federal retainers.

As I've been cleaning it up, I have noticed that some of the brass has a darker copper look to it. The
pictures don't show it well, but there is a difference. The headstamp tells me it's a little older.

I don't have any experience with brass cases older than the mid '70's, so I'm curious if these darker
cases are a product of age, copper content, ammonia? Nothing important here, just looking for education.

Patina.

That's what I was thinking as well. Kinda caught me off guard as I pulled them out of the
tumbler, as they were noticeably darker.

I am using Frankford and Denver arsenal brass, dated from the early forties, cleaned and annealed, in an 8mm-06. The color on it tends toward a very faint reddish copper hue compared to current production commercial. No signs of failure yet, 3rd or 4th firing.

Faint reddish copper hue describes it just right. I'm planning to anneal and use as much of it as I can. Hate to waste
much these days.

Sort by batch as best you can and annealing is a good idea. I have loaded and shot much grodyer looking cases with no problem. Might give them a wipe with Never dull or a stint in the tumbler or vibrator but they don't really need it.

Manufacturers do get different lots but they are pretty consistent in their specs so I doubt that is the cause.

It isn't patina. That is removed by your tumbling process.

Brass used to make cartridge cases can vary a bit in composition. Nominally the alloy known as "cartridge brass" is 70% copper/30% Zinc, but in practice the alloy may have rather less Zn, down to about 20%, and perhaps even a little less. The less Zn, and therefore the more Cu, the redder the material is going to be.

Another thing that can make the cases appear redder is dezincification, which is the selective removal of Zn by leaching/corrosion. When this occurs it seriously weakens the brass. You'd typically see white powdery corrosion product on the (unpolished) cases, and a degree of roughening of the surface if this was the case. You'd probably also notice signs of breakdown of teh boxes, and dezincification is typically associated with storage in damp conditions.

If dezincification isn't evident I wouldn't worry about the minor difference in colour. I'd be more concerned that the brass is sound. I'd check inside each case for signs of necking (incipient separation), and check the neck and shoulder for signs of cracking. If all's good I'd sort it according to weight, anneal the necks and put it into service.

Bingo, we have a winner^^

Appreciate the responses. That's the edumucation I was after. I have already tossed a few of the cases that
had white powder on them. The majority thus far at a glance look okay. I will inspect necks, shoulders,
and for signs of separation. I'll be at it a while, but I don't mind tinkering with brass. Always good to learn something.

Anneal the necks/shoulders and load them up. I routinely use '06 brass a lot older than that and it's good stuff- very uniform necks, etc.- and it all has headstamps of FA (Frankford Arsenal) late 20's to WWII. (I'm also still dipping into a stash of old Frankford Arsenal primers, FA-70's from the 1930's, but that's a story for another time. Corrosive as hell, but my-o-my what nice SD's of velocity they provide- better than some "modern" primers in the same loads and same guns. Of course, it means a thorough old-timey cleaning with hot soapy water after use, but WTH.)

I just recently pulled the bullets from a batch of FA-30 (1930) tracers to get the brass. Collector value be damned. The excellent brass is worth more to me than the money and hassles and risks of shipping it cross country.