I thought I would share this little trick, and see if anyone else has tried it. Almost 40 years ago I had a case knife that my brother in law gave me for Christmas. I could sharpen it razor shape put it in my pocket and in 2days it would need sharing. It just would not hold an edge. An older man told me to open the blade stick it Ina Irish potato and leave it over night. I did this and it turned the blade darker, but man it would sharpen so sharp it just jumped through anything and everything you put the blade to. And it held its edge seemed like forever. My best friend asked to use my knife and I warned him it was very sharp, he laid a piece of fuel line on the blade and pushed it with his thumb. It jumped through that line and half way through his thumb.