All the spice vendors always recommend glass for storing spices in a cool dark place. I have saved some of the plastic shaker jars like the Tones. I put my rub in those when I'm ready to apply. I have been buying Oak Ridge BBQ rubs lately. Superb product. Theirs comes in a high quality resealable vacuum pouch. When I'm ready to use it I will pour what I need into one of my smaller glass spice jars if I don't need much or a larger plastic Tones shaker when I am doing a larger quantity.
Oak Ridge also sells a nice stainless steel dredge that has just the right size holes that distributes their rubs very consistently and evenly. But it doesn't have a way to close off the holes so if you leave your spices in their they will go stale. I just return whats unused back to the resealable pouch when I'm finished.
Just thought I would update. I purchased some of these silicone lids that will fit over glass jars or the stainless steel dredges. They fit snugly and provide a excellent seal to maintain freshness. A little spendy but worth the price. Good product.
I store my rubs in glass quart Mason jars. I took a couple of the lids and drilled and deburred dirrerent size holes in them for different grinds and switch those "drilled" lids to the appropriate jar(s) when I'm using that rub...Also have a couple 1/2 quart ones for smaller quantities.