If you don't already have an email address for all your spam, get one, then change your email address in Facebook to that one. While the annoying emails still

If you don't already have an email address for all your spam, get one, then change your email address in Facebook to that one. While the annoying emails still get send, you are at least no longer bothered with it in your day to day email use. Not ideal, but slightly better. Of course you can also use email filtering rules, but seperating it physically makes it more likely you do not burn time on it by accident.