I broke a key off in the lock of a desk drawer. The lock doesn't look easily replaceable, so how can I remove it? I've tried tweezers but they can't get enough of a grip to pull it out.
I had this happen and used a pair of needle nose pliers. I had to buy a set of extra small ones at the store. There is an amazing assortment. I imagine that something like pliers made for electronics would do the trick.
In the past I've used a thin barbecue skewer to extract broken keys, I also found a set of eyeglass screwdrivers handy as well. It all depends on how deep it broke off of course.
EDIT: How you use the skewer depends on how the key has broken. Keys are commonly made of cast lightweight metals which have a rough texture with lots of pits outcroppings along the break. What you are trying to do is use the point of the skewer to get into one of those and then use the bottom or top of the lock slit as a fulcrum to pry the key out.
Alternatively if you can get the point into the top of the lock above the key you may be able to get the point in front of the rearmost tooth and then use to the top of the lock slit for leverage.
It may be useful to have more than one skewer, thin screwdriver, what have you available and use them in conjunction.
A locksmith would use a key extraction tool to remove the key.
You might be able to finesse it out with the tip of a small pocketknife or a dental pick -- try to get the point against the side of the key remnant and drag it out, using as little pressure as possible. If you can move it even a small amount you may be able to repeat enough times to get it to where you can use tweezers or needle nose pliers.
Pick up a "Scroll Saw Blade" from your local hardware store. They are nearly identical to a key extractor a locksmith would use. Just break the tip off the blade on the side that the teeth are facing towards. Then slide it in beside the key, turn slightly, and pull out. It may take a few try's but it works like a charm. Then find you a good bottle of bourbon and toast to yourself for saving money!