[If he had a bit more self-awareness at the moment he'd realize it's very rude to be staring but he's not putting two and two together. As it is he doesn't realize why Zuko's even more irritable suddenly and he settles for a small glare of his own.]

Everything does have a melting point. [Though it's the phrasing that catches his attention. "Bending" fire? He's not the first person he's met who can do such a thing but he never mastered that ability himself. Meditation with Wan...didn't go that well.]

It's not a bad idea. But how're you gonna get close enough to melt them without them melting you first?