How do you restore an old strop?

I came across 2 old strops in an antique shop today. One is a paddle style but the leather had broke loose at one end, the other is the normal handled strop but had some serious warpage and more bend to the left than a teenagers you-know-what, but seriously I'm interested in picking one or maybe both up and restoring them. The leather on the paddle style strop is pretty thin, does anyone know if there are replacement pieces for this style? And as for the warped one is there a way to soften it up and get the warpage and bend out of it?