Hello, I would like to derust our C3 at the folds Schweller/bodenblech below, outside; how would you proceed ? I mean the A4 riders, exactly 😉 The folds are partly three-layered, since the fenders are fixed in front and rear. If the rust has already wandered a bit high between the sheets, how do you get there ? From the outside it does not look bad yet. Thought maybe slightly bend up, sand off, paint and knock again ? But then the paint bursts off again … Many before underfloor protection from below in the bent fold spraying ? Thought already on entwined, but this is probably bad because of the heat . Greetings and beautiful WE