Crikey mate, how long is a piece of string??
Unfortunately, it not as simple as your question asks.
Bear in mind, I know nothing at all about your expertise in this field, so these questions may seem mundane to you.
It will depend on many factors, such as:
Can you properly identify what is the fiber in the rug??
Is it hand made or machine??
What is the stain??
Is there any uv, moth or other damage to the rug which may be affected by cleaning??
What is the value of the rug??
Can it be taken away for proper in-plant cleaning, or does the customer want it cleaned on-site due to other reasons which may include insufficient funds??
There are many other questions as well as the above.
As an example, a relatively cheap HSP ( Heat Set Polypropylene ), rug may even be cleaned on-site with HWE, Rotary, Cimex, OP or even a dry cleaning method, with reasonable results.
If you have a rug with urine, it generally needs to go into a soak tank with Acetic Acid to neutralize the urine crystals.
I say Acetic Acid because I won't name a proprietary brand here.
This brings us to another question, how will you dry the rug after cleaning??
Do you have, or have access to a drying tower, or will it be dried flat??
Just a few things to think about before buying a second hand rug.
If you are truly interested in cleaning rugs, just like leather, I would first do a specialist course with some of the top teachers over there that specialise in rug cleaning,
and preferably run their own successful rug cleaning plant, not just teach how to clean.
Hope this helps.
Short 1
I don't regret my past, I just regret the time I've wasted with the wrong people.
Take me as I am, or watch me as I go.
I'll retire when I can no longer do what I love, or no longer love what I do.
Stop moving, start dying........