So check this out!... now I know what to do with my oil!
"I often use mild steel found around my shop to make some minor parts, and depend upon a hardening of the surface to save the part from wearing excessively or rusting easily. Mild (low-cost) steel can be made fairly rust-free by a quick, cheap method, utilizing the used oil drained from your car. (This is also a good excuse not to be in a rush to take the drained oil to the recycling place until you’re good and ready.) The dirtier the oil, the better, as this is a rich source of carbon. I heat the part to a cherry red and quench it in the carbon-blessed oil, maybe repeating the process several times until I have a good blackening much like the carbonizing on camshafts and other parts of an engine. This surface is reasonably hard, but more importantly, holds up under the 96 percent average humidity found in the Southeast Gulf Coast of Texas. It simply won’t rust."
Case Hardening with Kasenit
I snagged it off this site.
I got a torch.. and I just changed my oil... still sitting in the collecting pot.
....I might try this on a craptastic blade.....
How to Harden Steel With Motor Oil | eHow.com