When I was a kid there was a knife sharpening truck that'd come to my block (Queens, NYC) twice a year. Think ice cream man / food truck, but for sharpening knives. They would take your knives, and you come back some time later and they're as sharp as can be. For straight blades you can do it yourself, but to hone something with serrations is much more difficult and they'd do it no problem. They'd also let curious kids watch from just outside the truck :)