I can see where aging an aro might not improve the flavor, in principle. But, you have moisture, sugar, and starches (as long as there aren't too much preservative), I would think that fermentation is possible, but it would have to be a blend that fermentation would benefit the flavor. But, most likely the issue you would have to deal with is mold from handling, especially a few ounces out of a bulk. I jarred up some of the first aros that I "tried out" before finding my blend spectrum. A couple of of the heavier cased sweet aros developed a white film of mold. And, I did try out a couple of cavendish blends recently to find that the flavors had diminished leaving behind just a nasty tasteless burly. It also had a bite that it didn't originally have. It had aged, but the aging didn't make it necessarily better.
Just like most, I hate to throw out a perfectly good tobacco. I have given away a few to friends looking to try out the pipe, but I just can't bring myself to throw them away. So, I will keep my jars till I have the urge to try out one of the non-moldy aros later, or maybe play with them by adding some other condiments to them.