diff --git a/test/unit/ajax.js b/test/unit/ajax.js
index 564f69267..f7c67b7be 100644
--- a/test/unit/ajax.js
+++ b/test/unit/ajax.js
@@ -763,7 +763,10 @@ test("jQuery.getJSON - Using Native JSON", function() {
 
 	stop();
 	jQuery.getJSON(url("data/json.php"), function(json) {
-		window.JSON = old;
+		if (!old)
+			delete window.JSON
+		else
+			window.JSON = old;
 	  equals( json, true, "Verifying return value" );
 	  start();
 	});
diff --git a/test/unit/manipulation.js b/test/unit/manipulation.js
index 465686fdf..541776ceb 100644
--- a/test/unit/manipulation.js
+++ b/test/unit/manipulation.js
@@ -626,7 +626,7 @@ var testHtml = function(valueObj) {
 	}
 	ok( pass, "Set HTML" );
 
-	window.debug = false;
+	delete window.debug;
 
 	reset();
 	// using contents will get comments regular, text, and comment nodes