Who does the machine belong to? Who pays for it when it wears out or breaks down? Are the iron castings a big earner? If the customer is paying enough money, wear that sucker out. If it's a tight-margin job, I wouldn't put that trash in any machine I owned.
I turned a couple of brake rotors on my old manual lathe. I laid wet towels across the ways to catch everything. It was a mess. I'd try to do something similar to the mill if it's a one-time job that absolutely needs to get done.
Don't forget that the machine also runs on linear guides. Those are going to get ground up too. Imagine what it'll do to the coolant pump. The list goes on and on.