How to get a security case of a cd?

I'm not a criminal, i bought 2 cds from the super market and I went through one of those "pay yourself" isles, and ive come home with 2 cds with security cases on them cause i didnt realise they had to be taken of in store? How can i get them of without driving all the way back to the shop? They are full cases surrounding the cd and i do not want to damage the interior. Thanks :)