How to use "melt" in a sentence

After the murderer kills the victim, they just watch the weapon melt

It didn't begin to melt; the room was cold.

By this time, we had passed the one-year mark in the development process, and I knew we were not going to wind up with a usable script, so I didn't insist on discussing whether the rubber tires would melt off the vehicle within two hundred yards or three, or ponder at what point the gasoline tank might explode