Restricting sales of new GCs in TNEW

We no longer want to sell gift certificates, but are still obligated to honor certificates that have already been sold. I can see how to make changes to the page in the Product Type Editor and Product Editor, but not how to turn the page off entirely. We don't link to it from anywhere else on our site, but a simple google search will still turn it up and someone did buy a GC this way over the holidays. The only other option I could think of was to inactivate the payment method in Tessitura, but that would make it so we cant redeem any of the already issued GCs. Can anyone tell me how to disable just the page for purchasing new GCs, without preventing old ones being used?