I have an old Swiss Army Knife on which I can only open one blade; the rest are locked in place. How should I clean this, and is there anything else I should do to refurbish it, like oiling, after I clean it?
This knife has been part of my daily carry for over a decade, and I carry it when I exercise, so I'm sure the innards are packed with some combination of pocket grunge, old candy and sweat.
The one blade I can still pull out works great, but the other blades are nice too.
When mine gets too bad I use WD40 to free it up, then clean with soapy water and a brush. Mine also goes through the dishwasher sometimes, with the blades partially open. If it gets gummed up with sugary stuff (your candy, or cutting up fruit) a good soak in hot water will free up the blades.
After cleaning it is a good time to sharpen it. If the hinges are still stiff, a drop of light oil (3 in 1 or bike chain oil) at each hinge should do the trick. Work the oil in by opening and closing all the blades a couple of times before assuming you didn't use enough, then wipe any excess off before putting it in your pocket. You could wrap it in a tissue the first day you carry it in your pocket, in case oil escapes when warmed by body heat - I used to carry one when I wore a suit.
The producer offers a page of care instructions on their website (here) (PDF). The gist is:
@chris-h's answer is also spot on. I, too, use a dishwasher (the producer discourages it). I saw some oxidation of the aluminium parts between the blades after that.
