89 300CE 200k+

Recently the shrouding on my cat rotted off. That dragging sound was sheet metal rubbing the road. I just pulled it all away. There seemed to be a little asbestos or some kind of white stuff between the shield and the cat.
Checking my records, it's been at least 80K miles since exhaust system installed. I'd like it to last even longer.
Is it worth knocking some tin to re-shape some protection? Or was it there only to keep the weeds on the dirt roads from burning? I'm in the Northeast and salt is an issue. I can't find a specific replacement for the part.
The exhaust makes no bad noises, sounds as good as ever.