By default, btrm does not remove directories.  Use the --recursive (-r or -R)
option to remove each listed directory, too, along with all of its contents.

To remove a file whose name starts with a '-', for example '-foo',
use one of these commands:
  btrm -- -foo

  btrm ./-foo

Note that if you use btrm to remove a file, it always be possible to recover all 
of its contents within 60 days, looking for deleted file at trash directory and
and use --recover options to recover whatever you want. For greater assurance 
that the contents are truly unrecoverable, consider using shred.