I have a friend that makes leather drive belts like these, and have talked to him about it a bit.

First, for drive belts you never put any kind of grease or anything on them except like neatsfoot oil or other leather dressing.....perfect for a strop!

Second, they are ALWAYS made of vegetable or smoke tanned leather since the alternative chemicals used to tan leather WILL corrode metal quickly.....perfect for a strop!

Finally, the leather has to be very uniform in thickness and free from surface blemishes since it will be riding on a convex pulley....Perfect for a strop!

I have a chunk of his scrap that I am going to use for a pasted paddle strop in a week or two and will get a longer piece from him to make me a new hanging strop whenever he has some spare leftover...

Thanks for the idea!