YOu may have to invest in some new rubber seals for canning jars, but they are relatively cheap, and are available at grocery stores, and hardware stores that sell the canning jars. You want to seal moisture out of the powder, and then store the jars in a cool dark, DRY place. If your basement is damp, its not the place to store powder, unless you take steps to isolate the jars from the moist air. You can put the jars in zip lock bags, for instance, to keep out the moisture. Buy some dessicant packs at a hobby shot, or at some hardward and home improvement stores, to use inside the bags to absorb any moister that gets into the bags. A 2 quart bag can hold a couple of quart size jars.
If you have access to one of the vacuum machines for putting plastic over things, and sucking out the air before the bag is sealed, you can use that to seal the jars from air individual, or in a group.