diff --git a/cmd/contacts/contacts.go b/cmd/contacts/contacts.go
index 0d0f601..ef0c363 100644
--- a/cmd/contacts/contacts.go
+++ b/cmd/contacts/contacts.go
@@ -14,6 +14,9 @@ import (
 	_ "github.com/lib/pq"
 )
 
+var all = flag.Bool("all", false,
+	"extract addresses from all messages. Default is to only extract from unprocessed messages.")
+
 type contact struct {
 	hash string
 	name string
@@ -91,13 +94,29 @@ VALUES (
 	errc <- nil
 }
 
-func fetchMessages(db *sql.DB) error {
-	rows, err := db.Query(`
+func fetchMessages(db *sql.DB, all bool) error {
+	var query string
+	if all {
+		query = `
 SELECT
     hash, blob
 FROM
     original
-`)
+`
+	} else {
+		query = `
+SELECT
+    original.hash AS hash,
+    original.blob AS blob
+FROM
+    original
+LEFT
+    JOIN contact ON original.hash = contact.hash
+WHERE
+    contact.hash IS NULL;
+`
+	}
+	rows, err := db.Query(query)
 	if err != nil {
 		return err
 	}
@@ -140,7 +159,8 @@ FROM
 			for _, hdr := range []string{"to", "cc", "from"} {
 				addrs, err := msg.Header.AddressList(hdr)
 				if err != nil && err != mail.ErrHeaderNotPresent {
-					glog.Errorf("%s %q header: %v", h, hdr, err)
+					glog.Errorf("%s %q header: %v: %q", h, hdr, err,
+						msg.Header.Get(hdr))
 					continue
 				}
 				for _, addr := range addrs {
@@ -169,7 +189,7 @@ func main() {
 	if err != nil {
 		glog.Fatal(err)
 	}
-	if err := fetchMessages(db); err != nil {
+	if err := fetchMessages(db, *all); err != nil {
 		glog.Fatal(err)
 	}
 }