Thinking about reducing maintenance on an antique, here's an example of a part that, by removing it, reduced coin inlet jams. It's on a mills Hi-Top quarter machine, with the tractor mechanism.
The function of the lever (red arrow) is to keep only one coin in play at a time. Once you insert a coin, the lever blocks the inlet path until that coin is played. Trouble was, the second coin in the staged area occasionally wouldn't release because that lever kept it hung up. I'd have to fish it out with a pick, or remove the bonnet cover to pluck it out. And also,sometimes the lever wouldn't fully return to it's normal position, thus preventing even the first coin from dropping down to the tractor inlet.
So I removed the lever.
Now, I can "stage" two or even three coins in the path without a jam - so far. It seems to have eliminated a common jam point.