Rashi: Like vanishes. Like smoke disappears, so make them vanish.

Malbim: This explains how Hashem will scatter His enemies. Just like in the Midbar, You led Yisrael during the day via a cloud, also now Hashem should be like a cloud of smoke that destroys the eyes. Just like in the Midbar, You led Yisrael at night via a pillar of fire, and the cloud scattered them, also now Hashem should be like a fire to eradicate His enemies, like fire melts wax - "u'Vara Hashem Al Kol Mechon Har Tziyon

Rashi: From in front of the Aron in the days of Moshe. "Uv'Nuchah Yomar Shuvah Hashem ¹

Radak: It is wax.