In January of 2006 (5 years ago) I bought vegetable shortening in 3 types of containers;
1) a hard metal can with a metal lid that had to be taken off with a can opener (which I don't think they make anymore)
2) a soft cardboard type container with an aluminum lining inside and an aluminum peel off lid protecting the product
3) a soft plastic container with a soft, white peel off lid protecting the product.
The shortening in containers 1 and 2 were still fresh but the shortening in 3 (the plastic container with the white peel off lid) was rancid.
(I was told quite a few years ago that shortening in the metal cans would last pretty much forever...so I'm going to wait at least another 5 years before I open another one of those.)
I can re-seal the good shortening that I've opened (and greatly extend it's shelf life) by melting it on the stove and carefully pouring it into quart canning jars while it's still hot and immediately placing the lids and rings on them. (I had 9 pounds of shortening and it filled 5 quart jars) Make sure the rims are free of any oil. As it cools, the lids should make that great "plink" sound and seal. If it doesn't seal, you can re-heat the shortening in the jar until it's quite hot and then replace the lid and ring. You can also vacuum seal the jars that don't seal after they cool. With the shortening in quart jars, you can see if they start to discolor and go rancid.
The Crisco brand shortening had the aluminum lined containers with metal bottoms and aluminum peel back lids. The WalMart house brand had the aluminum peel back lid but the container was made from the white plastic and was not aluminum lined inside.