YouTuber Andre Will Do It found a butcher's knife that was coated in rust, with pitting over 2 millimeters deep on both sides. He almost gave up before eventually restoring it to excellent working condition.
Here's where it ended up before he stained the new handle, which was impressively freehanded earlier in the video:
Bonus video: old rusty garden knife makeover:
• Rusted butcher's knife – Impossible Restoration (YouTube / Andre Will Do It)