Antique rusty lighter - Restoration project --- AF invention

Today I'll be restoring this rusty antique lighter. It has been damaged badly by the rust and is in urgent need of restoration. The whole top side had rusted and the stone didn't even move when I begun. Luckily the lighter is made of thick plate and the rust had not gone trough. The cap didn't have much extra material left though. After removing the rust I found stamp saying FZ 522 and the bottom of the lighter says 522 too.