These aren’t nearly as effective as dry ice because it’s hard to remove 100% of the oxygen.
Here are links to how to use oxygen absorbers
USA Emergency Types of absorbers and how many to use
USA Emergency How to package your food with oxygen absorbers
Here’s what Walton feed had to say about oxygen absorbers (not at their website anymore):
“If you are planning on using oxygen absorber packets in preserving your edible dry goods, you must be able to seal the container. The oxygen absorber packets absorb the oxygen, leaving a partial vacuum. If your container isn’t air tight, the oxygen in the air being sucked into the container will eventually load the packets with oxygen, and introduce oxygen back into your product. Air is about 78% nitrogen and 21% oxygen.
That’s about 646 cc of oxygen in an empty #10 can. Seeds take up between 50% and 75% of the volume in a can, leaving perhaps 161-323 cc of oxygen in a filled #10 can. The oxygen absorber packets Walton Feed uses and sells will actually absorb as much as twice or more of their rated capacity. They are not quite twice as big as the oxygen absorber packets used in the study on this page. Walton’s puts one oxygen absorber packet in their #10 cans and two oxygen absorber packets in their 6 gallon Super Pails. The oxygen absorber packets used by LDS canneries and in the following study will absorb 300 cc of oxygen.
All plastic breathes a small amount. If you want the best, use mylar bags which cut this air transfer down to almost nothing. These 4 mil thick bags have an outer layer of aluminum and 3 different plastic layers on the inside designed for a wide range of products including long term food storage. For all practical purposes they are light proof, air proof and water proof. These bags are strong enough to hold a partial vacuum, the main reason, in my opinion, you need them if you are going to use oxygen absorbers and plastic buckets. This is because as the oxygen absorbers absorb the oxygen in the container they don’t put anything back in, but rather create a partial vacuum. If you didn’t use the bag, your bucket would collapse instead of the bag. The buckets just aren’t strong enough to hold this vacuum without being seriously deformed. But the mylar bags can, even though they are thin. For those wanting the very best, these bags will protect your food inside the bucket even if for some reason the lid on the bucket didn’t make an airtight seal which seldom happens.
Several people have ask me if they can store food in these bags without putting them in a protective bucket. The answer is no. And that’s because they are not in the least puncture resistant. They really need that bucket for support. The bags we sell fit a 6 gallon plastic bucket perfectly. Before you start your operation, you may wish to cut a bag into strips beforehand to test making a few seams in order to get the temperature set correctly on your iron. You want to get the temperature of the iron set so after the bag is ironed closed you can’t pull the bag open without destroying the bag. It is also easy to get the temperature set too high which destroys the strength of the bag.”