How do I remove enclosure urls from rss feed?

Found a sollution on this problem here:
https://www.livexp.net/wordpress/get-rid-of-auto-media-enclosures-on-wordpress.html

It’s from 2009 but I use it on 3.3.1 and i still works

Simply put this in functions.php:

function delete_enclosure(){
return '';
}
add_filter( 'get_enclosed', 'delete_enclosure' );
add_filter( 'rss_enclosure', 'delete_enclosure' );
add_filter( 'atom_enclosure', 'delete_enclosure' );