diff --git a/tests/mocha/field_image_test.js b/tests/mocha/field_image_test.js
index 6b88bf5ff..0ef8055f7 100644
--- a/tests/mocha/field_image_test.js
+++ b/tests/mocha/field_image_test.js
@@ -127,9 +127,6 @@ suite('Image Fields', function() {
           console.log('on click');
         };
       });
-      teardown(function() {
-        delete this.onClick;
-      });
       test('JS Constructor', function() {
         var field = new Blockly.FieldImage('src', 10, 10, null, this.onClick);
         chai.assert.equal(field.clickHandler_, this.onClick);
diff --git a/tests/mocha/insertion_marker_test.js b/tests/mocha/insertion_marker_test.js
index 5449b7070..071043cfc 100644
--- a/tests/mocha/insertion_marker_test.js
+++ b/tests/mocha/insertion_marker_test.js
@@ -73,7 +73,6 @@ suite('InsertionMarkers', function() {
       delete Blockly.JavaScript['stack_block'];
       delete Blockly.JavaScript['row_block'];
       delete Blockly.JavaScript['statement_block'];
-      delete this.assertGen;
     });
     test('Marker Surrounds', function() {
       var xml = Blockly.Xml.textToDom(
@@ -214,9 +213,6 @@ suite('InsertionMarkers', function() {
         chai.assert.equal(xml, expectXml);
       };
     });
-    teardown(function() {
-      delete this.assertXml;
-    });
     test('Marker Surrounds', function() {
       var xml = Blockly.Xml.textToDom(
           '<xml xmlns="https://developers.google.com/blockly/xml">' +