Before videos and the internet there were these things called books.
Yes, one of the nice things about Marlins is remove the lever screw and you can take down the whole action.
With Winchesters, the 1873 model is the easiest to take down and clean. One screw to remove the side plates and the entire action is accessible for cleaning. Not so much the Browning designed guns like the 1892 and 1894. For them, I give the barrel a good scrubbing with a bore snake. I can't remember the last time I took a '92 apart. I don't think I have ever taken a '94 apart.