I like carbon blades but they do seem to start rusting as you shave. I swear they have rust stains before I can take the blade out of the razor. I now put a small amount of petroleum jelly on the edges.All my S/E razors are loaded with Gem Personna stainless blades or Pella ptfe's. Carbon blades are a waste of time and money.
They rust and dull way too quickly. For the purist,they should be classed as a hobby blade.