I got my Spiderman from the local pinball retail store after they had a warehouse fire. They brought in an ionizer and it worked great for them, with no electronic damage at all. Of course they had a big booth set up, so I'm not sure if there is a smaller option that works differently.
For my Spiderman, I just opened it up and let it air out for a few days, then cleaned it really well on the inside/outside of the cabinet with standard Clorox spray and put a fridge box of baking soda in there for like a month. You can't even tell it was in a fire now, other than the big scorch down the cabinet side.