The translation by Lattke1 (“Have = share salt among each other”) suggests that salt is a symbol of friendship at a meal. This translation does fit the call to have peace among each other but has no connection with the preceding verses (49 and 50a). Moreover, there are objections to this translation (1. ἔχετε is not “share”; 2. in 50b ἐν ἑαυτοῖς refers to everyone personally and ἐν ἀλλήλοις to the relations among each other).2
50 Salt is good, but if the salt has lost its saltiness, how will you make it salty again? Have salt in yourselves, and be at peace with one another.”