How to lubricate entry doors and what to use : Lithium Grease
Quote from Article entitled How to lubricate entry doors and what to use:
Using of engine oil will be perfect for lubricating typical locking systems;Sun flower oil is rarely used, but might be applied in emergency cases, if there is no alternative;Melted fat is a very strange yet popular method of oiling door locks. It produces an immediate and short-term effect, and eventually worsens the situation;Grease lubricant is widely applied for maintaining door locks, but is far worse than more up-to-date means;Lithium waterproof grease (for example, Lithol) is mainly used for bearings, but can also be of use for locks;Gun oil aerosol (for instance Gunex) works well at very low and high temperatures, which is good for oiling an entry door. It is able to dissolve consolidated grease lubricant, facilitating the working of the lock.
All in all, the best way to avoid expensive repairs of a lock, and the whole door construction, is timeliness in carrying out maintenance work. Especially since it is very simple to oil a lock and thus to extend its service life.
The full version of the article can be found here.