To “clear” a gun means to check to see if it is unloaded, and (if necessary) to unload it. It is always polite to clear the gun immediately before you hand it to someone else. It is equally polite — and expected! — to clear the gun yourself as soon as someone hands it to you, even if they did the right thing and cleared it before they handed it to you.

The actual procedure looks like this:

Gun Owner #1: “Hey, check out my new pistol!”

Gun Owner #2: “Love to see it. Whatcha got?”

As this conversation is going on, GO#1 drops the magazine, locks the slide open, looks in the chamber and the magazine well, and feels both chamber and magazine well to be sure they are really empty. Leaving the slide locked open, GO#1 hands the gun to GO#2.

As the gun is handed over, GO#2 looks in the chamber and down the magazine well, then pokes a finger in each spot to be sure they are really empty.

Only after doing these checks does GO#2 close the slide or do anything else with the gun.

GO#2: “May I dry fire?”[ref]It’s always polite to ask for permission before dry firing someone else’s gun. If it is a modern, quality centerfire gun, you really can’t hurt it by dry firing it. But some people haven’t gotten that memo, and get really weird about it. So always ask, and don’t pout if they say no.[/ref]

GO#1: “Go right ahead. It’s got a sweet trigger!”

GO#2, of course, always keeps the muzzle pointed in a safe direction, and still does not put her finger on the trigger without first choosing a deliberate aimpoint with a solid backstop. After choosing her safe direction, she tests the trigger and agrees that it is, indeed, very sweet.

When GO#2 is done exploring the gun, she locks the slide open again, visually and manually checks the gun, and hands it back to GO#1. GO#1 checks everything again before putting the gun away.