Hello,

There is a circular (galvanized?) plate in the bottom of the trunk of my car. It was sealed to the opening that it covers with a caulk type material probably from a tube. It is not like rubber or silicone but appears to cure and become tough. It is directly above the muffler but I do not think it really gets hot but the material should be safe for that type of application (heat, moisture). I was wondering if anyone knows what the substance is? Or a good modern substitute. Any suggestions?

Thanks!