Q: What can only be used…

Q: What can only be used after it is broken?
A: An egg.
Jokes, +1:
A man who is just married is flying to the Florida Keys for a business trip. His new bride is to accompany him the next day. When he gets there, he e-mails his wife to let her know he made it there safely. When he sends the e-mail, he mistypes the address. In Boston, a grieving widow, whose husband has recently passed away, receives the e-mail. She reads it, screams, and faints. Hearing her grandmother’s cry, the widow's 18 year old granddaughter runs into the living room to see the computer on, with a message that reads, "Dear love, I just got here. Preparing for your arrival tomorrow. Can't wait to see you. Love, Me. P.S. Sure is hot down here."