Guitarsandcars

Hey guys, So I have a 1981 Camaro and the past owner took it upon himself to redo the headliner in the car. He didn't use a foam back or the proper glue so eventually it sagged to the point where he ripped it off and thumb tacked the fabric into place. It honestly looked terrible so now that i'm finally redoing the interior, and don't really want to spend the $250 (That's how much it is for where i'm located) to get a new ABS plastic headliner board, what can I do to remove spray adhesive (I would hope that's what he used) off the old cardboardish headliner. I've tried a manual wire brush and that doesn't really do much. I've tried using my electric sander on it but the glue literally grabs the sand paper and rips it right off instantly. Ive tried manually sanding it but it gums up the sand paper way to quick. I'm considering getting a wire brush for my drill and trying that? Is there a product I can use to strip the glue without hurting the headliner backing board? I have some 'Goo Off' which might work for a bit and I know that 'Goof Off' would be WAY to strong for this

Thanks for all your help

PS. or am I just screwed and would it save me a crap ton of time just ordering a new headliner board based on the pics....?