I am importing time data, which imports in the hh:mm:ss format (or omitting
hh and mm if 0 value) to my eyes, but in the general format, so those entries
which could represent a time of day are interpreted as a time of day in the
AM, and that which could not be a time of day is interpreted as text.

e.g. "4:00" in a cell shows as "4:00 AM" in the formular bar and :40 shows
as :40 both places, but is formatted as text.

Prior to import, and to the eyes after import in the cells themselves, there
are five types of entries:
00:00:00
0:00:00
00:00
0:00
:00

How can I convert these text strings and time values to seconds? Can it be
done?