I have a pair of Arkansas stones that I've been using for over 30 years; a grey "medium" and a white "fine". The grey stone won't raise a wire edge any more for some reason. I've always cleaned them with warm soapy water after use to get the old oil off, so I don't think it's clogged. It just doesn't cut any more.
I have a 500 grit diamond plate for flattening water stones, would that work to restore the oil stone to working condition again?
TIA.