Phosphoric acid is clearly Works ...! However, it should be noted that this dissolution process really time consuming ..wer so is his rust times evenly, would quickly dissolve quickly but should pick up the blasting machine or just leave the car for the weekend! I have in a VW Transporter 4 (T4) the sill under the driver's door derusted (outside). So an easily accessible place that I have, of course with a drilling machine and steel brush attachment, pre-cleaned. (Advanced rusting, metal isolated up to 2/3 depth attacked) In Einstundentakt then the acid was applied with a brush. After about 11 hours, the sheet was blank as far as I could start with the processing!
