
I recommend a sonic cleaner. Three or four drops of Dawn dish washing soap and 4 or 5 minutes in the sonic cleaner and you will be surprised at how much gunk comes out of it.
WD-40 is great to remove water but its lubricating qualities are lacking, in my opinion. I use Quick Release Oil, it is the best knife oil I have ever used and I have used most of them.
For light surface rust most of it comes off easily with a #2 pencil. For deeper rust I use a rust eraser, an abrasive made in a rubber material. You basically user it like as eraser.
Like any experimentation it is best to start on old knives you know don't have great value.
Hope this helps.
