Trying out that Latvian "Rust-Off" rust converter. Works well, but not as nice as the Flag Paints stuff as it has no black pigment. No black coverage, just conversion. At least it goes on pale green so you can see where you have applied it.
De-rusted the Crossgolf's massive steel under-engine shield, then applied converter and next is paint.
New shield is somewhere around €160-200, so worth restoring. Used ones are just as rusty.