You are mopping it too much. No hardwood floor should be subjected to 5x per week of cleaning...
Dry swiffer it.
If the shine is gone - because of the over-cleaning...have someone come in sand them down (if they are real hardwood) and put a new gloss shine on it.
If you do the vinegar and water to get the gunk off - you can use the Orange glow product like this:
and it should help. STOP mopping every day. Dry swiffer and wet wash ONCE a week, IF EVEN..