Wrap one end of the jig saw blade with duct tape, if you are not using an extractor tool. Wrap the end that allows the teeth of the blade to point toward you when inserting the blade into the lock. Wrapping the end of the blade helps to protect your hands from cuts.
Spray the key hole lightly with spray lubricant. This helps the key to come out with less difficulty. Concentrate the spray in the area where the teeth of your key points in the lock.
Insert the key extractor tool or the jig saw blade into the key cylinder. The tool or the blade are thin enough to insert above the teeth of the key. The tool or jig saw blade move the tumblers off the key teeth as you insert the tool into the cylinder.
Feel around for a jagged cut on the key with the tool or jig saw blade. You'll know when you have a grip on the key.
Pull the tool or jig saw blade out of the key cylinder quickly. Watch for the broken piece of key as you remove the tool or jig saw blade.