A variation of this might be for you to identify people and firms doing office cleaning in your area. Find out if they clean carpets. Many do not. Offer to partner with them in a way that allows them to offer a more complete service. You do their carpet cleaning work for them, in return for referral fee to be negotiated between yourselves. You get new work, and they get an additional income stream for doing nothing except tying in with you. You could apply the same approach with individuals and firms which perform house cleaning services.