Previously for door locks I would give them a shot of de-icer from one of those little aerosol tubes they sell at walmart next to the ice scrapers. Recently on a residential door lock I used Remington Dri-lube with FANTASTIC results. It took 4-5 seconds of jiggling the key to get it into the lock, after a couple of sprays of Dri-lube into the keyhole with the straw, key slides in like they're magnetized. I am going to use Remington Dri-lube for all locks from now on.
I use Armor-all or Silicone Spray on a paper towel for the door seals.
I use Armor-all or Silicone Spray on a paper towel for the door seals.