Gents, I have noticed a soapy residue clings to the blade after a shaving session. It comes clean off when wiped with a towel, but I don't want to dull the edge by running it through the towel so I am left with a thin strip close to the edge of the blade (it looks like the sticky side of a Rizla). Shaving cream leaves a worse one than soap.

Any suggestions for how to get this off whilst preserving the edge?