First gen MINIs are notorious for getting cracked windshields. I had my share. After the last replacement (Safelite I think), I noticed the lower trim was popping up. I did nothing about it until the center sections were clearly unattached. I could lift up the trim and see at least one clip was broken. Got new clips and took off the trim to be greeted by this absurdity. Most clips had the crud on them.
Thankfully, the grey goop came cleanly off the clips and they were still usable. I will never use Safelite again.