Prep and paint stucco

I have a buddy that has an older house that has stucco. He is planing to paint it (it is painted now) and is going to get his paint from a paint store. He was asking me how I would wash and clean the stucco to get it ready for paint. He was thinking of using a pressure washer but I suggested a garden hose, some TSP and a stiff broom. Am I off base?