If you have trouble inserting and removing your key, or notice a grinding feeling when turning the lock, it is likely time for a little lubrication. However, it is important to choose a lubricant that will not collect dust or other debris and lead to further build-up. It should also be resistant to corrosion and not create a gunky mess in the lock mechanism when it gets wet.

Graphite powder is a well-known dry lubricant that has been used for decades to lubricate locks without attracting dirt or accumulating buildup. It has many useful properties, including refractoriness, high structural strength at elevated temperatures, low thermal shock resistance, very good chemical resistance, adsorption of x-rays and neutrons, and a relatively large surface area with low weight.

A variety of uses have been found for natural and synthetic graphite, ranging from common pencils to zinc-carbon batteries and electric motor brushes. Railroads often mixed powdered graphite with waste oil or linseed oil to create a heat-resistant protective coating for exposed portions of the steam locomotive boiler. Graphite of various hardness or softness produces different qualities and tones when used as an artistic medium, and the Scope soldering iron is an example of a commercial product made with graphite.

While a dry graphite powder is effective at lubricating locks and preventing buildup, there are better alternatives available today. The more modern lubricants such as silicone, WD-40, and greases-for-everything are petroleum-based and will leave behind an oily residue that can trap other particles such as hair or pocket lint and lead to further buildup in the lock mechanism.