He who scrubs the head of an ass wastes his soap.
More Italian Proverbs:
He who goes slowly goes safely and goes far.Italian
He has done like the Perugian who, when his head was broken, ran home for his helmet.
Italian
If you would have your work ill done, pay beforehand.
Italian
Rather have a little one for your friend, than a great one for your enemy.
Italian
The pope and a peasant know more than the pope together.
Italian
The more the fox is cursed, the more prey he catches.
Italian