function RemoveEditors(){
  var files = DriveApp.getFolderById("FOLDER ID").getFiles();
  while (files.hasNext()) {
    var file = files.next();
    var docs = DriveApp.getFileById(file.getId());
    var users = docs.getEditors();
     for (i in users) {
      email = users[i].getEmail();
      if (email != "") {
      docs.removeEditor(email);
}
}
}
}