Washing leather is a great idea, and if you read through specialized leather jacket forums, you'll find out lots of cool ways to do it. It takes off that shininess, especially on a lot of calf and horse, leaves a nice matte texture, and allows the jacket to break in a lot easier. A lot designers will wash leather, either before or after the make, to get more drape in the garment. That said, except in the case of horse, which is super dense, and will not shrink very much, even in a hot wash (I washed my ToJ FQHH jacket in hot water, heavy spin, and I would guess that it shrank maybe 2-3%, which was just enough), you need to be careful, because leather will shrink, and can shrink like crazy, a full 2 sizes, even. I remember one leather jacket, by KZO, that never made it to production (it was the year they closed down). Super cool, but on my 155 lb frame at that time, the medium was tiny. I would estimate that that jacket had shrank from a true 38 to between a 34 and 36. I could barely get the arms in, and the chest was several inches from being about to close.