Can I start a letter in Italian with "Buon giorno"?

Question

I don't know the name of the person I am addressing, so I can't put "Dear so-and-so" and I'd like it to be friendlier than "To whom it may concern". Can I start it with "Buon giorno"? Or maybe "Salve"?

Thanks in advance for your help. :)

Answer 1

As a rule you shouldn't start a letter with "buongiorno" since this literally means "good morning" and it wouldn't fit in case the addressee reads it in the afternoon or in the evening....!! Jokes aside, that's not really a nice starting for a letter.
A good, generic and informal start could be "Salve" as you suggested by yourself, otherwise if you prefer to be more specific and formal you should write "Egregio Signore".
In case you want to address yr letter to more people (even of mixed genders, male and female) you should write "Egregi Signori" while if it's addressed to a single woman you must write "Gentilissima Signora".
In any case don't forget to put the capitals same as I've done, being this the sign of your respect to unknown people.

BTW, in written Italian the one word buongiorno is way far more used than buon giorno