And if you do, how?  I used to load a lot of lead SWC's in 357's, and the shaved lead and lube would gum up the seating die in a hundred rounds or so.  So I'd unscrew the die, take it apart, and ream out the core with a bore brush.  Since I only load plated and jacketed bullets these days, that problem is gone, but I look at my 20+ year old dies and wonder if they need a good bath.  Some have rusted from high humidity, or oily fingers.  Is there a need to clean them?  It's amazing the questions I come up with while I'm loading a batch of ammo..... :roll: 
Papajohn