Most times, the "old" smell is a result of dampness.
Try to put a packet of silica gel into the bag, it will absorb all moisture and hopefully the smell.
Silica is toxic if ingested. So make sure not to keep it around pets or kids!
__________________ My Wish List: Gucci 1800 series Ladies Gold Tone Watch with Leather Strap
Coach Daphne Diamond SS watch
RM Stud Devotee in Wine - gunmetal hardware
Treesje Asher in Black
Michael Kors Uptown Astor Tote with gold hardware
I use the Odor-Out Bag Candies from lovinmybags.com.
You open the wrapping, and just place the whole thing inside your bag for a few days (zip closed if possible). It removes all musty, smoky, mothy smells and leaves a really nice scent behind!