I remove the lock plate as part of my ordinary cleaning protocol, because parts back there will need to be re-oiled, if not cleaned of soot, and residue, that has its ways of getting into the tiniest of cracks. It takes no time at all to scrub it with an old toothbrush, with soap and water, then rinse it under the faucet. I blow the water out of the nooks and crannies, and then set it aside to dry while I clean the rest of the gun. That includes scrubbing the barrel around the nipple or Th on a flintlock, with that same toothbrush, with soap and water. I also remove the nipple Every time, and give it both a soaking and and a scrubbing with that brush, to get the residue off my nipples. Then the nipple is dried, as is the barrel. The Flash channel is cleaned from the hole for the nipple. All this is done to the barrel after I clean the barrel with soap and water.
I dry and oil the nipple, and the threads in the bolster where it is screwed. I oil and check all the screws in the lock to see that they are snug, and then put the lock back in the stock. I check the gun's action for function, and then oil the outside of the lockplate, barrel, and other steel metal parts before storing the gun. This becomes habit. The last time I did this, It took all of 5 minutes to do these things. It takes longer to put my gun away, fill my powder horn with powder, and put more caps in my capper, than it does to clean my gun.