What kind of whetstone for sharpening a nylon edge? I have an unusual question on the topic of whetstone. Although this isn't a knife's edge, I thought that maybe someone here might be familiar enough with the types of stones to offer an answer.

When working on electronics I use nylon tools to prevent damage to the surfaces I'm working on. The problem with this is that I will quickly damage a tool either my losing its edge or by chipping and cracking. The edges of these tools are also fairly dull and I would like to give some of them a very sharp edge suitable for cutting (rubber and silicone in this case).

What kind of whetstone would be able to give me a very sharp edge on my spudging tool and allow me to recover an edge in the event that I damage the surface?

Here is a photo of the surface of the spudger:
I'd use fairly fine wet/dry paper taped to a hard  flat surface, probably used wet. You could move to a finer grade to finish. This will keep it nice and flat. 

Or you can shave/whittle the edge with a scalpel or razor blade. That's what I've done with a nylon spatula that I want a nice edge on, but on that the edge tends to deform rather than wear down, because it's used to push against hot things.