Strop cleaning.

[yamahog3187]

Every time I see a video of someone stropping a swivel knife,  the strop looks brand new. I realize that in the real world that doesn't happen, but I also know that the rouge and metal will build up in the leather over time. How do you clean this out of the leather? Is there a cleaner of some sort or do you just scrub it with a wet rag and get what you can out, let dry, and start over?

[Martyn]

I just scrape the build-up off with the edge of a metal ruler, then run 180 grit sandpaper over if to freshen up the nap and re-charge with compound.