a) delete with -x, --del
Displays the entire tasklist with numbered lines and asks which line to delete, then asks if you want to delete another line. A yes answer displays the edited list and asks which line to delete. Quits when you answer with other than y or Y.
b) delete with --clean
Removes all entries with due date older than today. Via magic :-)
c) with editor
$ todo -e
c) delete with -e, --edit
Opens the tasklist in a text editor. The default is nano and can be changed by editing taskferrc.