Share 'What to do about white stuff In "dry creek bed" checked finish?'

The photo tells the story. The back of the headstock looks the same, and there is a little of this on sides at the upper bout, and a spot on the back. Based on Frank's warning about using polishes on old finish in the "Cleaning" article on Frets.com, I am guessing someone tried to do just that (yes, it came to me this way). I have tried water, mild detergent, naptha, and denatured alcohol. In ...