cazman shampoo & conditioner from rens pet depot ROCKS!
best shampoo & conditioner I have used yet and I've been trying to find a good shampoo for a year and a half

Also, best shot vitalizing mist (from Rens also) is a MUST HAVE for preventing knots in the yorkies hair. Combing was a nightmare before someone recommended that mist and I use it for daily combing and to spray on after a bath; A + highly recommended. Good Luck!