Pics would indeed be helpful. You'll get lots of good advice here, but some may be overkill, depending on the condition of your knife.
Very generally speaking, my cleaning routine usually involves flushing out the joints & gaps with WD-40 or similar, then washing the knife in hot water with dish detergent like Ivory liquid or Dawn. Rinsing in hot water afterwards will warm up the internals and help evaporate off residual moisture. Dry everything you can reach with paper towels, rags, etc. Then re-lubricate the joints with your preferred oil or other lube. If the knife is very rusty, that's where some more aggressive methods might be used, like steel wool, sandpaper, etc. Don't want to rush into that, if it's more than what's necessary. But, I'd post those pics first and take some time to read other suggestions, as they come.