Does the fog smell sweet? If so, its glycol based fog. Being an unknown manufacture, who knows what else is in that fogjuice. Any good floor cleaner should be able to take it up. If it is still there, goo-gone or some type of orange clean will clean it up.
Rubbing Alcohol is very good at breaking down / cleaning up Glycols and glycerins. It's a bit more enviromentally freindly than Goo-gone. "Simple green" should work as well.
And of course, water works well with glycol cleanup too.