Kuroi is right... For security reasons it is NOT a good idea to have ALL details of a credit card in one place - be this in the database, on paper, memory cards, CD's or anywhere.
Zencart does not store all the details in the dbase anyway, so there's no mechanism to retrieve them all at once.
What if your office was burgled?
Your bank would - in all likelihood - hold YOU responsible for all fraudulent activity on those credit card numbers, and your insurance company would not pay out. You could be liable for many thousands of pounds/dollars.
Additionally, your bank will revoke your merchant account, and probably blacklist you, preventing you from opening a merchant account anywhere else.
If you are making paper copies of credit card details, it would be prudent to have a closer look at your Merchant Agreement...