Im with garyJ on this one, why lie.
I have had this on quite a few occasions, and simply told the custy that I would not be able to get staff to work under these kind of conditions.
However, I did once have a customer reply to me that they did not realise that it was that bad, and asked for my help to rectify the problem. We did a full initial clean, top to bottom, including carpets at great expense to the customer, and we still spend a couple of hours with her every week.
The customer is 91 years old, and has no family, relatives or friends to visit her. In my opinion we are providing her with an excellent service, and have without doubt improved the quality of her life.
Regards
Paul