Figure out what type of leather you are working with
To break in a jacket, the leather must be strong enough to withstand abuse. Lambskin is soft and luxurious but does not have the same tensile strength of Horsehide, Cowhide or Goatskin. Leather is not like fabric in the sense that you can stitch up a hole, marks and scratches are permanent on skins. It is important to choose a strong durable leather to really wear it in and make it conform to you.
Take it slow.
Anything you do to the jacket cannot be undone. Look at old leather jackets that are worn in and see where there is the most wear to the leather. Usually the collar, pockets, under the sleeves and elbows typically get the most wear from friction and rubbing. Leather will naturally break in unevenly over time so be sure not to be too precise.
Get caught in a light rain.
Water will soften up the leather and allow you to stretch and crease at specific points on your body. Many people will tell you to put your leather jacket in the washing machine and dryer, which is a very effective method but will cause serious shrinkage of the leather. In order to avoid shrinking your jacket significantly, wear it through a light drizzle until the leather is damp. Bend your arms, find a punching bag, or do some pushups, anything you can to get some wrinkles in the right places while the jacket is wet until it dries on you. If you can’t wait for the weather, lightly spritzing the jacket with water will work too, but just be sure to do it slowly and not to drench it. As it dries it will form to your body.
Rough it up.
To take off some of the finish in highly worn areas, use fine steel wool to lightly and unevenly scratch the surface. Sandpaper is generally too abrasive and harder to control. Remember to use uneven strokes and go very slowly to check out progress because you can’t go back and erase the scratches. However, the jacket will continue to change and break in over time so if you make a mistake just try rubbing this area more as you wear it to naturally break it in. Crumple the jacket in a ball, tie it up with twine and play catch with it, the more you throw it around and soften it up, the more it takes on your unique shape and fit.
There is no substitute for just wearing it.
Each Schott jacket starts as a blank canvas for years of wear and customization. Each scratch and nick tells a story unique to the person wearing it whether it is on their motorcycle for a cross country road trip or to the ball game and back.