can anyone identify this

[joy7]

I found this piece of metal (think tin) 2 x 3 1/4 while cleaning out the ash of my 4 year large wood flush xtrodinair a week after the insert was cleaned by my dealer. It was the first time the insert was cleaned. No one can identify it. since then I've hear bangs as if metal is expanding or contracting. I am having problems getting the fire hot and lasting . I've also seen smoke coming from behind the first brick closest to insert door. Im hoping someone can help me.