I use my Buck knife 125, same knife used for deer. You really don't need a knife very much to skin squirrel. I always slice the skin about the middle of the spine then I grab each side and pull the hid clean off each way. Its quick and works great. A little tip is pull the skin off and then field dress it. Makes for a clean carcass. Another tip is squirrels are easier to clean before they stiffen up. When I'm hunting I take a few ziplock baggies and paper towels and clean them in the field right after shooting them
I use my Buck knife 125, same knife used for deer.
Ditto , but a 110 here.
Correction, I meant my 110 as well. Another thing I use is diagonal wire cutters to cut off front and rear feet and the tail after you pull the hide off. All in all squirrels are not as hard to clean as they look.