Remove efflorescence and cement haze from facade

On the weather-exposed side of my house, ugly cement residues and efflorescence have formed on the cladding after 10 years. On the north side, there are several white spots in the area of the base. I tried to clean the facade, but on the weather-exposed side, this was not successful at all. The hardware store recommended hydrochloric acid for cleaning. However, that seems somewhat too aggressive to me; I definitely don't want to damage the facade. Does anyone have an idea how I can gently remove the efflorescence and cement residues?

There are cement residue removers based on hydrochloric acid. This effectively removes the efflorescence. You should be able to get the cement residue remover at a well-stocked hardware store. I do not recommend buying hydrochloric acid and diluting it yourself.