What about plastic bags, like zip-locks?

While plastic bags can form a reasonably good barrier to moisture, keeping the tobacco ready to smoke, the polyethylene that is used for most plastic bags is quite permeable to gasses. You can smell tobacco through the bags, after a time, and all that "aroma" that‘s getting out is stuff that you really want to keep in! For my 8-oz bags, I use a high-barrier film that forms a barrier to both water and gasses. These will not only keep the tobacco at the perfect smoking moisture, but will also allow aging to take place. This just won‘t happen with plastic bags, even those that are used with kitchen heat-sealing machines. For short term, like keeping an ounce around for smoking, plastic bags are fine. For long term storage, fuggedaboutit.

Next articles: When a good pipe goes sour, does it have to be discarded?