A lot of my colleagues and friends, including myself, have been in the position where recruiters/head-hunters make contact proposing certain jobs for certain annual salaries. In order to filter those a bit, just let the recruiter know:
"Hi [enter name here]! Thanks for considering me for those job-proposals, if the expected gross annual salary is above [enter amount & currency here], I would consider your proposed opportunities and might switch jobs"
Some recruiters might wrongly assume arrogance on your side and will be put off, on the other hand every person has a certain market-value and such a 'filter' saves time on your side and on theirs.
If a persistent recruiter doesn't acknowledge your request to only forward job-proposals that meet the mentioned criterias and still spams your inbox with a dozen uninteresting gigs, then a follow-up email or an immedtiate black-listing/block will guarantee relieve.. ;)
But keep in mind that on the other side, as @jefflunt wrote:
"A recruiter who you like working with, can actually become a partner in your career. Recruiters are usually motivated to get you the most money they can, so setting a bar is often very helpful. They can also be another voice in helping you know if your salary ask is too high or too low - if you're over-experienced and underpaid I'm sure many recruiters would love to help you get that raise."
As @Alan_Dev wrote in the comments:
"Recruiters don't want to waste their time, 90% of them will find a clear response like this very helpful and will appreciate it."
Good additional point made by @Benjamin:
"If you have additional qualifiers, such as preferred location, responsibilities etc. then mention them to your recruiter. Good recruiters like when you know what you want, because it makes it easier/faster to find fitting jobs for you. The recruiter might even answer they have no fitting job right now for you, but will get back to you once they have something fitting!"