Well, not old, exactly....but used.
I recently came across a CI article from last summer about re-using dill pickle brine to make fresh pickles and it works! Blew us away. As in, completely gobsmacked. I just had to share.
In a nutshell, slice a cucumber, salt it, then pour boiling brine over it. Cap, fridge, wait....et voilá, dill pickles! So simple, so foolproof. We even forgot to salt/drain the pickles and it still worked, it just took an extra day or so for the pickles to get as soft as a good hamburger slice should be. That's ok, though, because at day 3 the flavor was spot-on to the original. We used Claussen, but the article doesn't specify, so I'm guessing your favorite brand will work, too.
You've been doing this for years, right? So how come I'm just hearing about it now? Hmmm?