18/03/2014
Did you know a mop was first used in the late 15c and by definition was a bundle of yarn, etc., fastened to the end of a stick for cleaning or spreading pitch on a ship's decks.
Note it was used for spreading and this is what a mop does, it spreads the dirt from where you see it all over the floor so you can no longer see it.
Sorry to break it to you but if your floor is still wet when you are finished mopping it is still dirty.
There are more modern methods that get better results.