Again encountered on the site of one of our advertisers: Rustyco, "liquid sandpaper".
The stuff is watery and can be diluted or sold as a gel. Of course we already had it in the shed. But apparently that is not yet the case with everyone.
Rustyco is harmless to people, the environment, paint and other things and cleans pore deep. The virgin vulnerable bare metal must then be protected against new rust.
In combination with Fertan, this approach should lead to the eternal life of sheet metal or chassis parts. After all, Fertan has been used in industry, shipping and in car and motorcycle restoration for more than 30 years. And it works well in our climate even without the mandatory wetting of the substrate
Rustico and Fertan are no 'Tell Sell' panacea, but simply do their job chemically / chemically and effectively.
NOTE: These types of products work on steel and against rust. These products do not work (well) on a dirty greasy surface..