Temperature changes, weather exposure and moisture eventually take their toll on the mechanisms inside a lock. Dirt, dust and grime also build up in the lock's cylinder. Over time, this can make the lock cylinder tight and difficult to operate with the key. The most effective way to loosen a tight lock is by strategically spraying its internal components with a special lubricant designed for locks.
Insert the lubricant's supplied, spray-directing straw into the can's spray nozzle. Point the nozzle away from your face as you insert the straw.
Position the straw near the center of the lock's key hole. Spray short bursts of lubricant into the key hole.
Spray a small amount of lubricant on the lock's key. Avoid spraying lubricant on the portion that you hold to turn the key.
Insert the key into the key hole and pull it out again. Repeat the key insertion and removal several times, to lubricate the lock's cylinder pins.
Rotate the lock cylinder several times with the key. This helps to distribute the lubricant evenly around the pins.