Waypoint Management

Last summer I created waypoints for a trip using BC.
I've created new waypoints for this summers trip in BC.
I am unable to delete last summer's waypoints from my device using BC. I go through the motions in BC and delete them from Internal Storage but they always reappear and I can not remove them from the device (Garmin Edge 810). I am going crazy.

Is there a good resource that describes the data management of BC and Garmin units. I am getting a lot of errors using the trial and error approach.

Garmin 810 with memory card.

Thx
Dan