It wouldn't seem that hard to remember: when you're going on a plane, you need to leave your knives at home.
Since Sept. 11, 2001 -- almost six years now -- airports have been searching passenger's hand luggage for any item that could be used as a weapon. Though the defintions of "dangerous" have changed over the years -- some liquids are now forbidden, while some lighters are now allowed -- common sense dictates that certain items just don't belong in the cabin of an airplane.
But, of course, people manage to forget about the restrictions. About four million people are traveling by plane this holiday weekend, so that means there'll be plenty of new business for the people in charge of re-selling all that contraband. And, for you, it could mean a great deal.
As Early Show national correspondent Jeff Glor found out, every day, hundreds of passengers are discovered carrying potentially dangerous items. They are given a choice -- to check the items or hand them over. Most people chose the latter.
And what happens to all those items? Glor went to Atlanta's Hartsfield International Airport, the world's busiest airport, to find out.
"We've seen somebody try to bring a kitchen sink through. We've seen people in hurricane situations try to bring through a fully gassed chainsaw," said Ellen Howe, a TSA assistant administrator. But once these items are confiscated, where do they go?
Steve Ekin runs the state surplus warehouse where he sells what is left behind at Georgia airports. His merchandise, which is classified as "voluntarily abandoned to the TSA," comes in by the truckload.
"We're getting about 200, 250 pounds every two weeks of just abandoned property," - items that range from the menacing to the bizarre.
Ekin showed off a few recent additions to his inventory.
"These are real magazines?" asked Glor.
"These are real magazines," replied Ekin.
"That hold real bullets?" Glor asked.
"Absolutely," said Ekin, "absolutely."
Ekin then showed Glor a knife with a six-inch blade. "Someone actually tired to come on to an aircraft with this," Ekin said.
And then there was the 25-pound dumbbell, just the thing "for a little light workout," Ekin joked.
When the items arrive, Ekin sells them to the public. Everything is priced to move -- small knives are a dollar. Large knives go for as much as $3. The prices are a dream for bargain hunters like Ron Holt, who regularly drops by the Georgia surplus store.
"I come here not looking for something, I come here to look. I mean, there is no rhyme or reason as to what shows up. I mean, I've bought spear tips for scuba diving. I've bought, you know, kitchen knives, I've bought tools."
Ekin said it amazes him that after the strict rules have been in effect for almost six years, that people still try to carry some items onto planes.
"We'd hope that by now some of the folks would get the idea that you really can't carry this stuff any more. We really don't want it, so please leave it at home, keep it in your car, whatever you need to do," he told Glor.