[GreenKeys] sound proof material in mailbox

[Rokumon Cat]

Hi,
 
I was wondering if the sound proofing material inside the model 15 "mailbox" contains anything that I should be aware of, such as asbestos or similar harmful things. I am going to be powerwashing the mailbox (sans TTY of course), but before I do that I need to remove the sound deadener.
 
I just want to be careful about that stuff.
 
Thanks in advance!
 
Joe