Turning the magneto by hand can produce high voltage. Most original sills don't stand thorough cleaning. Be carefull with sand blasting a Traction. Doors and bonnet can't stand blasting with even the slightest bit of too much pressure. I've seen a lot of abused panels so be aware.
General rule is to only have edges and corners sandblasted.
Stay clear of large areas. And always clear off any sort coating before the sandblasting. Blasting this stuff of will result in holes. There is only one way to eradicate rust in door tips or bottoms. Cut off the lower part of the remaining structure.