I had saves some small plastic containers and we filled them with water. Now you can put drops of polish onto the water and they will spread out. Just keep dropping the polish into the centre so you get some rings. Next you take some toothpicks and drag the ring edges into one another to create the marbeled effect. Last you dip the object to be marbeled into the spot you like best (slowly and carefully) and take off any nailpolish that is still on the surface with a Q-Tip, that saves on clean up time. And thats it already, as easy as pie.
Watch out, though, the varnish dries quickly as soon as it hits the water and you might carefully have to remove the outer rings of "skin" so you can do the marbeling with the toothpick.
DO IN A WELL VENTILATED AREA!!!
Here are the results we got :
My oldest sons Dominoes, he did most of it all by himself! (I am so proud!)