Good Morning,

Cannot seem to delete pinpoints from mission to mission. Please advise how to do this.

If you are talking about the pin you set in manual flight go to map, tap on Pin (green diamond), and then delete pin point.

I drop pins some times in an automatic mission, and they are blue and there does not seem to be a way to delete them....

Blue pins (diamonds) are the upcoming waypoints being shown if that is what you are referring to.