Recently I received a couple kydex sheaths from a well known custom maker. These are for my 911 and 411. They are top notch, but the fit is a little snug around the knife handle on the 911 sheath. I really have to yank on the sucker to get the knife out. I have heard of the hot water treatment but am worried about getting rust on my blade. How long do I need to leave the knive in the wet sheath? Should I be concerned about my sykco getting rust from this application?