I have a Norton fine India bench stone that's eleven inches in length and I went thru a brief period using nothing or just a little water to 'float' the particles off the stone. And now I'm back to using oil. It seems that where 'grey' matter has built up on the surface there's a little less feedback, I feel less grinding as it were and therefore that's where the swarf has clogged the stone. To remedy the situation I've cleaned the stone with kerosene and aggressively brushed the surface with a brass 'toothbrush'. That procedure seems to have removed some of the swarf. Any comments, anyone? BDL?