If your front door lock starts to get a bit sticky, squirt a tiny amount of WD40 (using the very fine nozzle) right into the lock. It should ease the mechanism immediately.

Try rubbing the your key with a soft pencil – the graphite should lubricate the lock.

You can also use spray on cooking oil. Aim it directly in the lock.

wd 40 sprayed onto your key than put in lock and turn