I removed my Mossberg 500 from the trunk of my car. I noticed that the "safety" was getting lazy. It would shift position upon firing.
Dinking around a little bit revealed that the safety screw was loose. And did I do the smart thing and simply tighten it? Noooo!
Little dinky pieces parts dropped down into the bowels of the action.
I have done thorough and complete breakdowns/cleaning of my Mossberg 500 before. There are many good videos on Youtube.
What they do not tell you is how to create anti-gravity to hold all the little slider bar pieces-parts in place while you whirl-and-twirl the weapon as you reassemble it.
You cannot beat having some stout magnets when reassembling a Mossberg 500. They are also extremely handy for holding small parts.
Another "trick" that makes life easier is to use coffee filters. Coffee filters are made from a paper with exceptional wet strength. They are great for cleaning and lubricating parts. They can also hold small parts in a pinch...but be sure to put it off to the side so you don't grab it when hyper-focusing. And there is nothing preventing you from putting a magnet in the bottom of that coffee filter paper parts holder.
Finally, a piece of plain white paper makes a decent place to put your itty-bitty parts magnet. These old eyes are not getting any better at seeing stuff.
Old Mossy is back together and we are both happy.
And yes, the safety now functions the way it is supposed to.