Please don't remove the firing pin unless really necessary. If there's crud behind it, just flush the area with a solvent (WD40 works for me). The pin is sometimes staked/expanded during assembly to the cocking piece. Threads can be damaged during unnecessary disassembly.
So when should you clean the pin and bolt assy, after a certain amout of rounds, usage, years? I just got backing from shooting mine and it shot great, just the usual amout of "field cleaning"?