Want to get past a door chain without causing any damage? This could be handy if you have a door key (or you've just carded your victim's $hitty spring-latch lock) but your spouse (or victim) put the chain on before going to bed and you don't want to wake (alert) everyone up by knocking, shouting, ringing the doorbell, or kicking the door in.

Get a fairly long piece of string. Tie a slip-knot at one end of the string.

Now, open the door as wide as the chain will allow. Unless you're Popeye you should be able to get your arm through far enough to touch the knob at the end of the chain.

Now tighten the slip-knot around the little knob and run the string up over the top of the door toward the hinged edge. Make sure the chain isn't caught on the string.

Close the door while pulling on the string. Unless the grooved door plate has been installed so there is absolutely no slack when the knob is aligned with the open end of the track the string should pull the chain out. The lesser the angle of the string, the better, so that you are pulling the chain toward the hinges as much as possible, rather that upward, which can cause it to bind in the track.

It might take a couple of tries but the chain will eventually come out.

If there is no slack - even with the door closed - you can always use the hook and elastic method: Get a peel-and-stick hook and an elastic. (You do have these along with your duck tape and rope right?)

Reach in and stick the hook to the door so it's along the same line as the track. You are going to be hooking the elastic between the little knob at the end of the chain to the hook you've stuck on the door (a thumbtack also works if the door is wood) so want the elastic to be as taut as possible at all times

Slowly close the door and the elastic will pull the chain out of the track. Again, it might take a couple of tries if the chain binds at the end of the track.

If you really want to do this on a regular basis, you could rig a stick-on hook with an extension that pulls the chain inward and outward away from the door as you would if you were taking off the chain by hand, lessening the chance of it binding.

If you're the one who prefers to not sleep with one eye open while enjoying the security of speaking to someone without opening the door all the way, you might want to get the hinged alternative (see picture). You should also have a metal-clad front door. It not only holds up better against forced entry, but is also non-flammable, giving firefighters a lot more time to get you safely out of your apartment/condo window.