A new Express came home with me a few years ago. I stripped the receiver and began cleaning only to discover that there were many sharp edges and snags inside. For better or for worse, I grab a Lansky stone and begin lightly going over every edge and snag until I can freely wipe down the receivers internals without my cleaning cloth snagging on something, or feeling like I might slice open my hand.
On the plus side, the action was now amazingly slick. A very nice surprise.
On the minus side, some of the finish may be removed and require oil to prevent rust, but so-far-so-good.
If you try the same, it would not be at my advice -- the risk is yours.