What is the correct way to handle spam on MathOverflow? Can regular users do something when they see a spam post?

Safari is bugged in my macbook. It's a macbook air 2019 with mojave 10.14.5 The problem is I can't delete bookmarks nor save new ones on it because it ask to keep or remove firefox bookmarks, which according to Safari, where imported on january 1st 4001. I've pressed every button, but nothing...