An Ardsley spa worker has been arrested for allegedly offering clients more than just massages.Police say 45-year-old Chi Lan Yan, of Queens, was arrested Wednesday at the Sky Health Spa for engaging in prostitution activities.Authorities say they became suspicious when they noticed only men entering the business. A similar bust was made last week by police in Chappaqua at the Wen Wen Spa. Police arrested two women from Queens for giving massages without a license. One of the women was charged with prostitution. Cops say Yan was also wanted for outstanding immigration violations. She is being held at the Westchester County Jail.