diff --git a/scripts/symbols/clear_project_symbols.php b/scripts/symbols/clear_project_symbols.php
new file mode 100755
index 0000000000..cd1df72f2e
--- /dev/null
+++ b/scripts/symbols/clear_project_symbols.php
@@ -0,0 +1,48 @@
+#!/usr/bin/env php
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+$root = dirname(dirname(dirname(__FILE__)));
+require_once $root.'/scripts/__init_script__.php';
+
+$project = id(new PhabricatorRepositoryArcanistProject())->loadOneWhere(
+  'name = %s', $argv[1]);
+if (!$project) {
+  throw new Exception('No such arcanist project.');
+}
+
+$input = file_get_contents('php://stdin');
+$normalized = array();
+foreach (explode("\n", trim($input)) as $path) {
+  // emulate the behavior of the symbol generation scripts
+  $normalized[] = '/'.ltrim($path, './');
+}
+$paths = PhabricatorRepositoryCommitChangeParserWorker::lookupOrCreatePaths(
+  $normalized);
+
+$symbol = new PhabricatorRepositorySymbol();
+$conn_w = $symbol->establishConnection('w');
+
+foreach (array_chunk(array_values($paths), 128) as $chunk) {
+  queryfx(
+    $conn_w,
+    'DELETE FROM %T WHERE arcanistProjectID = %d AND pathID IN (%Ld)',
+    $symbol->getTableName(),
+    $project->getID(),
+    $chunk);
+}
diff --git a/scripts/symbols/import_project_symbols.php b/scripts/symbols/import_project_symbols.php
index 4ff2a3f2cd..b09fc6f377 100755
--- a/scripts/symbols/import_project_symbols.php
+++ b/scripts/symbols/import_project_symbols.php
@@ -30,6 +30,11 @@ EOSYNOPSIS
 $args->parseStandardArguments();
 $args->parse(
   array(
+    array(
+      'name'      => 'no-purge',
+      'help'      => 'Do not clear all symbols for this project before '.
+                     'uploading new symbols. Useful for incremental updating.',
+    ),
     array(
       'name'      => 'more',
       'wildcard'  => true,
@@ -151,12 +156,14 @@ foreach ($symbols as $dict) {
     $path_map[$dict['path']]);
 }
 
-echo "Purging old symbols...\n";
-queryfx(
-  $conn_w,
-  'DELETE FROM %T WHERE arcanistProjectID = %d',
-  $symbol->getTableName(),
-  $project->getID());
+if (!$args->getArg('no-purge')) {
+  echo "Purging old symbols...\n";
+  queryfx(
+    $conn_w,
+    'DELETE FROM %T WHERE arcanistProjectID = %d',
+    $symbol->getTableName(),
+    $project->getID());
+}
 
 echo "Loading ".number_format(count($sql))." symbols...\n";
 foreach (array_chunk($sql, 128) as $chunk) {