Frank, you can obtain the International Coupon Reponse at your post office; usually, small post offices don't have them so you may have to go to your main post office. It's a 3 x 5 (i'm guessing) coupon - cost about $2.10 - You include this coupon with your letter requesting a document.
These coupons are not widely used and are hard to find but they exist.
Regarding my Italians ancestors, I only have 2 plus that 1 in Corsica and some of their descendants are still alive so I can always contact them - someday. We hardly communicate. They live in France and Corsica. I live in Florida.
Thanks again for your help and don't hesitate to contact me if you too need help with your researches.