I'm in the process of addressing our invitations. I bought exactly 15 accommodations cards (letting people know about the hotel block) because that is how many out-of-town guests we are having. Right now, I am about 2/3 of the way done addressing, and I just realized that I have an extra accommodations card left over, meaning that I forgot to put it in one of the out-of-town guests' envelopes. Like an idiot, I have been sealing envelopes as I've been going along, so now I have no way of knowing which envelope I forgot to put it in. So far, I've done 8 out of the 15 out-of-town envelopes. Is there any way I can get the envelopes open without ruining them? What should I do? I'm really upset and kicking myself over this.