You could sharpen that, sure, but to get all the nicks out you’ll want to use power tools.

Me being me, at the beginning of every season I use my belt grinder to rework my mower’s blade to the extent that you can shave arm hairs with it, or handily chop a Post-It note clamped in the bench vise in twain. My mower is electric so I tell myself this is for battery efficiency purposes. It certainly doesn’t stay that sharp for long, but it’s nice to know that it’s possible.

If you remove any meaningful amount of material, make sure the blade’s weight distribution is even between both ends before you mount it back up. There are fancy jigs you can buy for this purpose, but I just stick a pencil through the mounting hole and let it balance itself out. If one side winds up higher than the other, grind a little material off of the spine of the blade on that end until it wants to naturally settle parallel to the Earth if it’s allowed to freely seesaw like that. Then mount it back up and send it.

Running a blade that is significantly out of balance causes expensive and inconvenient crankshaft or bearing damage eventually. So don’t.