There are multiple ways of finishing leather edges, including using products such as waxes, dyes, or gum tragacanth, but this post will focus on the tools and supplies suggested in the Atelier Louise Silver Sands Sandals pattern.
Edge beveler: This tool is useful for slightly rounding the edge of cut leather and can also do the same on synthetic materials such as soling (it just trims the sharp corner off, giving it a smoother, rounder edge). It is optional, as you will see in the Silver Sands Sandals pattern, but it does give a nice finish. You can purchase these tools in a variety of sizes, with larger sizes removing more leather. I recommend using Size 2.
Beeswax: Rubbing beeswax onto the cut edge of the leather (for example, on a sandal insole) seals the leather and also enables you to achieve a professional looking burnished finish when rubbed with an edge slicker (see below). Beeswax is also useful for waxing thread when you are hand stitching your leather shoes or accessories.
Edge slicker: These items can be made from wood or nylon, and both types work well. You can use a slicker to rub the waxed leather edge by hand, or attach it to an electric drill for faster results. Alternatively, if you already have a bone folder (it doesn't need to be made of actual bone, the nylon ones work well), you can use that to rub and burnish the leather edges instead of the edge slicker.