O.K. guys....I've been shooting traditional black powder for several years now, but I am somewhat new to flintlocks.  I bought a Cabela's trade musket about a year and a half ago, and due to work restraints and other factors, I haven't been able to get out and shoot it as often as I like.
  One of the things I notice is that I don't get many 'sparks' out of a flint....seems I get 6-8 good ignitions, then nothing!

   Not even the "flash in the pan".  I am using both english and amber flints, with roughly the same success.  Should I be cleaning my flint and frizzen off after each firing?  Not really sure why I am not getting a decent shower of sparks.
  Anybody got any insights?  Thanks in advance.