I would also suggest one of those pocket aerosols filled with alcohol. There is a stainless door and an o-ring that are supposed to block water, they may have failed. Even so, the spray will get your doors working.

Lubricating a lock is a big issue. My feeling is that no lubrication is best. If that doesn't work for you, then the lubricant that leaves the least amount of deposit...maybe a silicone spray. I don't like graphite, because it tends to build and clog, especially if you get frustrated and keep lubing it. Grease or oil are really bad, because they attract dirt. Lubrication will only make things worse if the cylinder isn't spotlessly clean. The real deal is to disassemble the cylinder and clean everything thoroughly. It's delicate work, but if you have the skill and tools then that's the ticket. Again, the alcohol sprays are you friend, since they will both clean and deice.

I keep reading about steel keys, but I would really be surprised if there were every any steel keys. Plated brass, yes. But steel would be harder and tougher than the bronze pins and would create a lot of wear. I've never had chipping from brass keys, that sounds like mythology too.