Have a look at the approach adopted by Hazrat Ibrahim (AS) to address his people:
69. And recite to them the story of Ibrahim (Abraham).
70. When he said to his father and his people: "What do you worship?"
71. They said: "We worship idols, and to them we are ever devoted."
72. He said: "Do they hear you, when you call (on them)?
73. "Or do they benefit you or do they harm (you)?"
Ponder over these Holy Verses and guess the prophetic wisdom and wise and mature attitude. He did not degrade the falls gods of his people and nor he called them with offensive names. Had he done that then in all probability they wold have burst out and would have declined to listen at all. So Hazrat Ibrahim (AS) put them in the situation to accept the truth themselves. So :
74. They said: "Nay, but we found our fathers doing so."
(Hazrat Maulana Syed Abul Hasan Ali Nadwi (RA), Armughan, October 1996AC p.22)