(Warning; recruiter talking here.) It's probably hard to stop my spammy 'colleagues'. If I'm correct they are sending you messages to your private email address

(Warning; recruiter talking here.) It's probably hard to stop my spammy 'colleagues'. If I'm correct they are sending you messages to your private email address, so we're not talking about LinkedIn here? Perhaps you can create rules in your inbox that automatically put messages with the subject containing "job opportunity" directly in your spambox. The spammy recruiters aren't very creative in the mail titles, so look for the common patterns and direct-to-spam those. If we are talking about Linkedin, I know a guy that uploaded an avatar with him wearing a clowns wig, that stopped a lot of recruiters approaching him :-).