I find ivy's virtual buffers feature (
(setq ivy-use-virtual-buffers t)) very handy for navigating to files whose buffers have been closed. Like ido's virtual buffers,it uses recentf to present those files as if their buffers were still open when switching buffers.
However, occasionally I want to remove clutter from ivy-switch-buffer by removing 'virtual buffers'. ido has
C-k, which does what I want. I've found that ivy's kill action does not always work for this purpose.
How can I reliably remove virtual buffers from the ivy-switch-buffer list, preferably using ivy itself?