how to remove body foam?

[mechanic021]

I have a 2 door blazer that I need to fix some surface rust on. its in the cab corner areas inside the truck. Well there is this foam sound insulation stuff covering up the rusted areas. I cant even get this stuff to pry off so how could I get this foam stuff out? Thanks for your help !

Mike

 

[MONMIX]

I HATE that stuff.
Usually I just cut, chop, scrape, burn what ever.