Hi Michael,
in answer to your question, the internet was correct, MS cannot be hardened as it does not contain enough carbon for the process to be successful. As Kwil said though, you can case harden the item.
This involves increasing the carbon content in the 'skin' of the item, usually just a few thou' of an inch, this can then be hardened. It is used a lot to prevent wear insuch a case as yours. There are lots of recipes on the internet for a 'home brew' approach, these usually involve ingrediants which have a high carbon content such as charcoal, leather, and bones. These 'recipes' are to be found on gun making sites and forums especially in the USA. However I bought a quantity of a high carbon special powder from Ebay where a relatively small quantity was available for a few pounds.
The process involves heating the item to red heat and dipping it into the powder and holding it at red heat for a while then repeating the process. This produces the 'case' which can then be hardened by cooling rapidly from red heat in water – some folk use brine or even oil. If you go for the homebrew approach, the item is packed tightly with a carbon source in an airtight tin and heated to red heat and held there for a while, I have used a domestic wood fire for this. Attractve colours and patterns can be obtained with different 'ingredients.
Have fun,
best regards
Terry