According to the Emily Post Institute, customers should tip between 15 and 20 percent for spa facials. The Institute suggests a similar tip percentage for other beauty-related services, such as haircuts, manicures and pedicures, waxings and massages.
Spafinder recommends that customers leave cash tips at the front desk. The receptionist organizes tip money and distributes it to the spa specialists at the end of the day. Customers should not attempt to find facialists and hand the tip money over in-person. Otherwise, they may interrupt someone else's relaxing spa experience and inconvenience the facialist if she does not have a ready hand or place to store the cash tip.