how can I delete duplicate contacts

My contacts keep breeding. I have 10 copies of some contacts. I started out with 1500 contacts 2 years ago. I am now up to 7000. There must be a way to delete duplicates. I have a Q10 release 10.2.1.3014
Its driving me crazy. I love the phone but this is nuts.

Do you have them syncing from several acct's, turn them off and use just one.