I cant delete some of my contacts in livemail (2012)

On 5 or 6 only out of 300 contacts I have in WLM 2012, the delete button is nto highlighted, so I cant delete them. These seem to be contacts which have been automatically created, either from import or some other way, because they all have very little detail, mostly just full name and sometimes a partial home address.

Any ideas on how to delete these unwanted contacts?

Thanks
Bob