Received a pair of leather boots as a gift, and am wondering how to waterproof them? Anybody have recommendations?

By the way--for all you folks committed to buying US-made products--this company makes really super-high quality boots and shoes (for men and women) in Pennsylvania. Each pair is handmade. The business is Vintage Shoe Company--been around for over 100 years and still going strong. (No, I don't work for them!)