I am just throwing this out there. I watch my Grandfather take his old double edge razor blade he shaved with, he put one in a old ceramic coffee mug(like the old white ones they had at diners) take his index finger and position the razor blade on the inside wall of the mug. He would slide the blade with his index finger back and forth inside the mug(half circle) and hold the mug with his other hand. Now I was pretty young when I watch him do it and I asked him why he was doing that for, his response this was how you stretched a dollar back in the great depression. I can tell you those blade were sharp enough to shave with again and again and again.
Chris