I have always used the whole board (not split into two pieces and wedged shape piece as some do), writes a Massachusetts trapper, and made as follows:
For mink I use a 3/8 inch board about 40 inches in length, 4 inches wide at the large end, tapering to about 2 1/2 inches at the small end with the edges planed down from near the middle of the board to the edge, leaving a thin edge and sandpapered down smooth. I make the board of this length for the reason that it sometimes happens that a mink may have laid in a trap for several days before being taken out, and if under water it is not always easy to determine the exact length of time it has been in the trap, and there may be a possibility that if put on the board to dry that having laid so long it will taint before it will get thoroughly dry. I have seen them in a case of this kind where several and perhaps nearly all the hairs on the end of the tail would shed or pull out thereby damaging the skin to a greater or less extent.
Now when I get a mink in this condition after pulling on the board and tacking all around, I split the tail open after which I lay it open and tack all around the same way you would with an otter skin. By employing this means you will often save the loss of the tail by thus tainting and a corresponding loss on the value of the skin. The value of the mink skin is in no way damaged by this process. Some dealers prefer to have all the skins they buy cured in this manner.
For stretching the muskrat skin I also use a board of the same thickness as for mink, about 20 inches in length, 6 1/2 or 7 inches at the large end with a slightly rounding taper to a width of about 3 inches at small end, the sides planed down to a thin edge the same as for the mink boards; in fact, I prefer the same manner of stretching all cased skins, using care not to have the boards so wide as to stretch the skins to a width much exceeding the natural width before it was placed over the board, but giving them all the strain they will stand with reason, lengthwise. If stretched too wide it tends to make the fur thinner and lessens the value of it.
I usually pull the skins, especially muskrats, onto the boards far enough so that the smaller end will extend through the mouth of the skin for perhaps 1/2 inch, and when the skins are sufficiently dry to remove, all that is required is to take hold of them with a hand on either edge of the skin and give it a sharp tap on the small end, when the skin will come off at once. By stretching the skins on the boards with the back on one side, belly on the opposite side, they come off the boards looking smooth and uniform in width, and command a great deal better price than if thrown on in a haphazard way on a shingle or an inch board badly shaped, as a great many beginners do. I have seen some shameful work done in this respect.
It is always necessary to remove all surplus grease and fat which can readily be done immediately after the skin is stretched, otherwise they will heat, sweat and mold to a certain extent after they are removed from the boards, which injures both the appearance and sale of them. It is well to look after all these little details. These descriptions are given with the desire to help some of the beginners. If they will start in by using a little care in stretching and having pride in their work they will find the business both more pleasant and profitable.
If convenient when going into camp, writes an old successful trapper who has pursued the fur bearers in many states, you should take several stretching boards for your different kinds of fur with you. If not, you can generally find a tree that will split good and you can split some out. It is usually hard to find widths that are long and straight enough to bend so as to form a good shaped stretcher. You should always aim to stretch and cure furs you catch in the best manner.
In skinning you should rip the animal straight from one heel across to the other and close to the roots of the tail on the under side. Work the skin loose around the bone at the base until you can grasp the bone of the tail with the first two fingers of the right hand while you place the bone between the first two fingers of the left hand. Then, by pulling you will draw the entire bone from the tail which you should always do.