The unforeseen problem with driving on the beaches in Normandy was that the sand got everywhere, and as we were staying in a static caravan, I didn't have any facilities for removing them and cleaning the sand off, so over time the sand has hardened into something which laughed in the face of my manual or electric wire brushes.
Looking on the trasure hunting forums, it seemed that acid was the way to go, so I have been cleaning them with a solution of acetic acid and water, in an ultrasonic jewellery cleaner:
After three session of 8 minutes each, then drying and a quick brush over to get the film off, they come up nicely:
Adrian.
