Rashi on Exodus 30:19/רש"י על שמות ל׳:י״ט

1את ידיהם ואת רגליהם THEIR HANDS AND THEIR FEET The priest washed his hands and his feet simultaneously. Thus we learn in Zevachim 19b: How was the procedure in washing hands and feet? He placed his right hand upon his right foot (knee) and his left hand upon his left foot (knee) and thus washed both simultaneously.