Making fire with flint & steel

[Mr. 16 gauge]

I bought a flint and steel last year while we were in colonial Williamsburg, VA. I used it most of the winter last year to start fires in the fire place (practice makes perfect ), and I dug it out a while back so I could practice some more as winter is approaching. Unfortunately, the steel doesn't seem to want to make the sparks it did before! I've tried putting a new edge on the flint, but that doesn't seem to work. Is there some way or something I can treat the steel with to get it to produce more sparks? The face is smooth, but so is the face of the frizzen on my musket.
Any thoughts or tips would be appreciated.