diff --git a/resources/sql/autopatches/20180914.audit.01.mailkey.php b/resources/sql/autopatches/20180914.audit.01.mailkey.php
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20180914.audit.01.mailkey.php
@@ -0,0 +1,26 @@
+<?php
+
+$commit_table = new PhabricatorRepositoryCommit();
+$commit_conn = $commit_table->establishConnection('w');
+$commit_name = $commit_table->getTableName();
+
+$properties_table = new PhabricatorMetaMTAMailProperties();
+$conn = $properties_table->establishConnection('w');
+
+$iterator = new LiskRawMigrationIterator($commit_conn, $commit_name);
+foreach ($iterator as $commit) {
+  queryfx(
+    $conn,
+    'INSERT IGNORE INTO %T
+        (objectPHID, mailProperties, dateCreated, dateModified)
+      VALUES
+        (%s, %s, %d, %d)',
+    $properties_table->getTableName(),
+    $commit['phid'],
+    phutil_json_encode(
+      array(
+        'mailKey' => $commit['mailKey'],
+      )),
+    PhabricatorTime::getNow(),
+    PhabricatorTime::getNow());
+}
diff --git a/resources/sql/autopatches/20180914.audit.02.rmkey.sql b/resources/sql/autopatches/20180914.audit.02.rmkey.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20180914.audit.02.rmkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_repository.repository_commit
+  DROP mailKey;
diff --git a/src/applications/repository/storage/PhabricatorRepositoryCommit.php b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
--- a/src/applications/repository/storage/PhabricatorRepositoryCommit.php
+++ b/src/applications/repository/storage/PhabricatorRepositoryCommit.php
@@ -25,7 +25,6 @@
   protected $committerIdentityPHID;
   protected $commitIdentifier;
   protected $epoch;
-  protected $mailKey;
   protected $authorPHID;
   protected $auditStatus = DiffusionCommitAuditStatus::NONE;
   protected $summary = '';
@@ -116,7 +115,6 @@
       self::CONFIG_TIMESTAMPS => false,
       self::CONFIG_COLUMN_SCHEMA => array(
         'commitIdentifier' => 'text40',
-        'mailKey' => 'bytes20',
         'authorPHID' => 'phid?',
         'authorIdentityPHID' => 'phid?',
         'committerIdentityPHID' => 'phid?',
@@ -321,13 +319,6 @@
     return mpull($audits, 'getAuditorPHID');
   }
 
-  public function save() {
-    if (!$this->mailKey) {
-      $this->mailKey = Filesystem::readRandomCharacters(20);
-    }
-    return parent::save();
-  }
-
   public function delete() {
     $data = $this->loadCommitData();
     $audits = id(new PhabricatorRepositoryAuditRequest())
@@ -605,7 +596,6 @@
       'phid' =>  $this->getPHID(),
       'commitIdentifier' =>  $this->getCommitIdentifier(),
       'epoch' => $this->getEpoch(),
-      'mailKey' => $this->getMailKey(),
       'authorPHID' => $this->getAuthorPHID(),
       'auditStatus' => $this->getAuditStatus(),
       'summary' => $this->getSummary(),