The bad news,, Sanding a dull blade will sharpen the blade just enough to cut ya good

There is no safe way other than to build a Magnetic Jig with Rare Earth Magnets, that jig will keep your fingers pretty safe...
Plans for such a Jig are buried here in the workshop You just need to search it out...

Or go slow and be careful,, BTW super glue does a good job at sealing cuts on fingers Muhahahaha