PB Blaster is a penetrating oil that is a much better penetrant that WD-40. WD seems to lubricate better but does not penetrate as well (my experience) It may be best to remove the lock cylinders and put them in a plastic cup and submerge them in PB for a few days. I would let them soak and try to work the key once a day. If this does not do it - start looking for doner lock cylinders! Dave
New locks all the time on ebay..I got a complete set for about $49---going to install when I get the Comet painted...currently have 5 different keys and sticken door locks.