Well, I mean the often fuzzy 'under' side, or flesh side, of veg tan leather......
There is some people who think that a smooth backside to the leather means a higher quality. A smooth back (flesh) side of leather is merely achieved in the tanneries when they split the hides to get them an even thickness.
However, often it is nice to have the back of your project nice and smooth, a belt, for example.
There are a few ways of doing this - here are the two methods I use most often.
If you use Eco-Flo Water Stain (the one in the square bottle) on a belt or project, use the stain on the back as well - it will slick down the flesh side beautifully and should not bleed off on clothes after you have sealed it with a finish. I have carried a piece of leather with this Pro Stain on both sides - no finish - in my pants pockets for a year and there was no bleeding at all.
Get hold of Gum Tragacanth. You can apply that a little at a time and rub down the back of the leather with an old spoon. To smooth it down even more permanently, you can then cover the back of the leather with Super Sheen - an acrylic product that will effectively seal off the back of the leather.
Both these products are available at your local leather supply store or they should be able to order it for you.
The belt piece before anything is done to it - you can see the typical loose fuzzies on the back.
After the gum has dried on the leather you can see the difference between the covered part and the untreated part.
This is a very upclose of the treated back side of the piece of belt.This post from August 2007 has been updated. The gentleman in the videos is my long time friend and mentor, Larry Moskiewicz