What melted in the fire that was precious to Ishmael? What is this symbolic of? (chapter 12)

Beah's rap cassettes melted in the fire,

As I was putting on my new army shorts, a soldier took my old pants and threw them into a blazing fire that had been set to burn our old belongings. I ran toward the fire, but the cassettes had already started to melt. Tears formed in my eyes, and my lips shook as I turned away.