How sharp should the edges be on one of these for muskrat and mink?

I tried one right "out of the box" and it did not work well at all.

The edge is pretty rough, not what I would call sharp at all.

If you're using it for mink and muskrat only- very little fleshing is needed, I use my scraper but you could use a butter knife or spoon and be fine. I like mine a little sharper for running over boarded Beavers one last time.

I use the one handle one for muskrat, mink and fox. I had to use that one edge sharpener in mine to get it to work. Every once and a while I touch it up with a steel. But its still not sharp, kind of like the edge of a butter knife, if that makes sense.

The one handed scraper does not need to be extremely sharp to work effectively, under pressure to re remove excsessive meat and fat, but it must be a smooth edge, not rough.

I have had my one handed scrapper for 30 years Its never been touched with a file. A nice rounded off edge Is what you want for rats and make sure the corners are rounded off so you don't have and sharp square edges that will dig Into the pelt. If you need a thin edge then your removing more then you need to on a rat pelt. We use to just run them through a washer machine hand cranked wringer and that was good enough. Most trappers OVER FLESH their rats.

I agree, have never sharpened mine since I purchased it. I use mine primarily for muskrats and for minor touch ups on other pelts. For mink, I use a fleshing knife made from a old plastic snowmobile glide rail.

Are they good for possums, or should one just use a regular fleshing knife?

I would think so as they are for smaller pelts and finishing tough spots on larger pelts. Myself I prefer the "strirrup" style as they have no sharp corner to worry about.

Thanks