The first step in restoring a vintage saw is to remove the handle. All too often, the sawnut/bolt assembly has become frozen over time—and it's always far easier to clean the sawplate without the handle, or if you have some horn repair ahead of you. But how do we deal with that danged frozen sawnut/bolt assembly that just won't unstick? Well for starters, we have to get a purchase on it. . . .
Nothing too large—a 10-incher will do. Break out your drill—you're going to bore a hole in it.
Bore a 3/4" to 7/8" hole in the clamp, about an 1.5" down from the tip. The intent here is to clamp your saw in the clamp, and access the frozen nut through the hole.
It helps to remove the other sawnuts/bolts that aren't locked up. You want as much wood on handle contact as possible. The clamp will hold the sawbolt in place while you torque the sawnut out.
Make sure your slotted screwdriver is ground thinner, such that you can fully insert the tip inside the sawnut to avoid deforming the edges.
A note of caution here: make sure when tapping out the sawbolt, that the handle is supported on either side of the sawbolt, so that you have a void to tap the sawbolt into—otherwise you'll wind up deforming the shank of the sawbolt.
So that's it: the concept is to clamp your saw tightly with a wooden clamp you've bored a hole into to access the frozen sawnut. Pretty simple, but someone had to tell me how to do it, too.