Natural fiber meaning some type of grass, or wool?
We don't see enough sisal/hemp/jute to worry about turning them down. Too many bad things happen, too rare that the rug cleans up well, too often unhappy customers no matter how well you prequalify.
We'll clean a rug on-site if protecting the surroundings is less of a pain than moving it, but we'll never use
compound. People pay us to get rugs clean.