It is extremely difficult to remove an older darker stain and white wash over it because there is always some residue of stain or varnish that will show through the whitewash. It will look blotchy unless you put in a lot more time than it would be worth. You would be better off refacing them and whitewashing that new bare wood. You could also paint them for about half the cost of refacing, though, painting cabinets is very tricky because every square inch of the surface must be thoroughly washed and etched. Waxes, silicone in spray polishes and oil from our hands actually get imbedded in the lacquer surface of stained cabinets and do not all come out with washing alone. Therefore you need to sand the entire surface to remove a thin top layer of the original lacquer (or varnish or enamel paint) to get down to a clean dull finish.