There is an old story that I picked up from a friend that went through JC Penny's customer service training regarding a woman, a restaurant owner and a pickle. Lets see if I can relay it correctly.
So a woman is at an airport when she sees a man she knows to be the owner of her favorite hometown restaurant. Since they know each other, she approaches him and they chat for a bit. Eventually the owner asks why he hasn't seen her or her family in a while. She tells him "You know, this may sound funny but I love your pickles and they used to give me an extra pickle when I ordered my sandwiches, but now they charge me an extra quarter and I have to ask for it." The owner was able to do some quick math and figure out how much business he was losing from this family not coming in and also the math to figure out that the cost of one pickle spear. He quickly apologized and invited the woman's family back out the restaurant saying he would fix that immediately. Obviously the cost of that pickle did not make up for the loss in that family's business. According to the story as I heard it, the restaurant owner got ahold of his managers and told them...you guessed it "Give them the pickle!"
Now as a cleaning company we may not ever be in the position to give a client a free pickle, but what we can give them is the above and beyond style service that knowing their preferences (preferred fragrances, recognizing the client's employees by name) and not nickel and diming them to the point of frustration. If an extra dollar of expense a week will help a $200 a week account sign their next contract, by god, give them the pickle! You spend an incredible amount of time bidding and grooming potential accounts, to prevent one from leaving is much easier and less costly than finding a new one.
The International Janitorial Cleaning Services Association offers to all it's members the opportunity to enroll in customer service certification training. You can find a list of IJCSA members in your area here: http://ijcsa.org/Janitorial-Service-Directory-Find-A-Janitorial-Service-JanitorialServices