removes / modifies user profile fields

remove-user-profile-fields.php

function modify_contact_methods($profile_fields) {

    // Remove old fields
    unset($profile_fields['twitter']);
    unset($profile_fields['googleplus']);
    unset($profile_fields['facebook']);

    return $profile_fields;
}
add_filter('user_contactmethods', 'modify_contact_methods');