diff --git a/oauth3.core.js b/oauth3.core.js
index 9cab6cb..5774c10 100644
--- a/oauth3.core.js
+++ b/oauth3.core.js
@@ -473,7 +473,7 @@
           var providerUri = oldSession.provider_uri;
           var clientUri = oldSession.client_uri;
 
-          Object.keys(oldSession).forEach(function (key) {
+          Object.keys(['access_token', 'token', 'client_uri', 'refresh', 'refresh_token', 'expires_in', 'provider_uri', 'scope', 'token_type']).forEach(function (key) {
             oldSession[key] = undefined;
           });
           Object.keys(newSession).forEach(function (key) {