I dont know what to do with my floorboards?

i had my floorboaads in the living room sanded and varnished a few years ago and despite regular cleaning, because of my 2 kids and dog they are now quite dirty and stained i want to re-varnish or paint them but dont want the hle of sanding them i was told a while back by somebody that there is a product that you rub on and it acts similar to a sander and strips away the dirt and old varnish has anyone else heard of this and do they know what its called where i could get it and how much it cost thanks