In order to avoid the accumulation of dust inside the lock you want to use a dry lubricant.
Key lock cylinder lubricant.
Slide the key in and out of the lock several times to spread the lubricant.
New keys and imperfect copies are notorious for.
Don t apply household oil to the key or cylinder because it attracts dirt and eventually would gum up the lock spray the lubricant into the keyhole itself and then spray it on the key.
Be sure to hold the lubricant six to eight inches away from the cylinder so that the wd 40 does not all get sprayed into one spot.
Realizing this the following section was designed to provide much needed answers to ensure that you purchase the best lubricant possible for your individual situation.
Wd40 inox or any oil based lubricant.
If stabilizing the cylinder on your house s lock doesn t work it might not be a loose plug causing the problem.
First clean the keyhole with a penetrating lubricant like wd 40.
Lube the lock with a dry lubricant.
Exercise the key and cylinder several times to ensure dispursement of fluid film throughout all of the cylinder components.
After you ve applied wd 40 to the lock the interior pins should disengage with no resistance and the cylinder should easily rotate when you turn your key.
It is also recommend to lubricate or clean the area within which the sidebar is located when the plug is at rest locked.
Lubricate the locks around your home with wd 40 regularly to keep them maintained.
Wipe excess lubricant from the face of the cylinder with a cloth if necessary.
Spray a dry lock lubricant such as 3 in one lock dry lube into the keyhole.
Spray the lock cylinder with the lubricant.
Insert your key and move it around to spread the lube into the lock.
Insert the key into the lock and turn it in both directions to spread the lubricant over the cylinder.
I always carry a can in my van as its great for lubricating lock mechanisms inside the lock body and for breaking down grease especially dried up grease which i sometimes come across in locks.