Remove post content in RSS feed?

One way is to use filters like:

add_filter( 'the_content_feed', '__return_empty_string' );
add_filter( 'the_excerpt_rss', '__return_empty_string' );

to remove the post excerpts and post contents from the feeds (atom, rss, rss2).

But note that this will not remove the corresponding XML nodes from the feed, only their contents.