Also, If you need to use a magnetic base close to it, put the base in a sandwich bag before locking it down. Even with bases with on/off switches, if you turn it "off" the swarf will stick to the bottom of the base. With the bag, you can take the base out and no swarf on it. How do I know this ?

experience the hard way - cleaning that swarf off the magnetic base is a serious PITA.
And the outer skin on CI is the worst; a lot of the time there is still casting sand embedded in it. Try to take that off with a single deep undercut, else your cutting bit will blunt very quickly. Then immediately clean the swarf from your machine, as this "first-cut" swarf will cause the most damage to your machine. Machining the cleaned cast iron, while messy, is less harmful to your machine, but do give everything a thorough cleaning when done machining the CI.
I've found that using a really sharply honed HSS cutter after taking off the skin and using aggressive cuts, produces less of a mess, as the swarf coming of makes bigger chips and less dust. So far the worst culprit for me with working with CI was doing single-point threading on it - that produces a very fine dust...
Cheers, Arnold