diff --git a/browser/components/sessionstore/test/browser/browser_248970_a.js b/browser/components/sessionstore/test/browser/browser_248970_a.js
index 64008a780a45..2bacdb5d7455 100644
--- a/browser/components/sessionstore/test/browser/browser_248970_a.js
+++ b/browser/components/sessionstore/test/browser/browser_248970_a.js
@@ -67,7 +67,6 @@ function test() {
   // sessionstore service
   let ss = Cc["@mozilla.org/browser/sessionstore;1"].
            getService(Ci.nsISessionStore);
-  let ss_interval = gPrefService.getIntPref("browser.sessionstore.interval");
   // Remove the sessionstore.js file before setting the interval to 0
   let sessionStoreJS = profilePath.clone();
   sessionStoreJS.append("sessionstore.js");
@@ -138,7 +137,7 @@ function test() {
         gBrowser.removeTab(tab_A);
 
         // record the timestamp of sessionstore.js at the end of the private session
-        gPrefService.setIntPref("browser.sessionstore.interval", ss_interval);
+        gPrefService.clearUserPref("browser.sessionstore.interval");
         gPrefService.setIntPref("browser.sessionstore.interval", 0);
         let endPBModeTimeStamp = getSessionstorejsModificationTime();
 
@@ -151,7 +150,7 @@ function test() {
           "outside private browsing - sessionStore.js timestamp has not changed");
 
         // cleanup
-        gPrefService.setIntPref("browser.sessionstore.interval", ss_interval);
+        gPrefService.clearUserPref("browser.sessionstore.interval");
         gPrefService.clearUserPref("browser.privatebrowsing.keep_current_session");
         finish();
       }, true);
diff --git a/browser/components/sessionstore/test/browser/browser_346337.js b/browser/components/sessionstore/test/browser/browser_346337.js
index e42750ff8194..407888c456ed 100644
--- a/browser/components/sessionstore/test/browser/browser_346337.js
+++ b/browser/components/sessionstore/test/browser/browser_346337.js
@@ -93,7 +93,6 @@ function test() {
   waitForExplicitFinish();
   
   // make sure we don't save form data at all (except for tab duplication)
-  let privacy_level = gPrefService.getIntPref("browser.sessionstore.privacy_level");
   gPrefService.setIntPref("browser.sessionstore.privacy_level", 2);
   
   let testURL = "chrome://mochikit/content/browser/" +
@@ -120,7 +119,7 @@ function test() {
             ok(!compareFormValue(tab, xpath, fieldList[xpath]),
                "The value for \"" + xpath + "\" was correctly discarded");
         
-        gPrefService.setIntPref("browser.sessionstore.privacy_level", privacy_level);
+        gPrefService.clearUserPref("browser.sessionstore.privacy_level");
         // undoCloseTab can reuse a single blank tab, so we have to
         // make sure not to close the window when closing our last tab
         if (tabbrowser.tabContainer.childNodes.length == 1)
diff --git a/browser/components/sessionstore/test/browser/browser_350525.js b/browser/components/sessionstore/test/browser/browser_350525.js
index f0b2ef97ead8..369d42e4f712 100644
--- a/browser/components/sessionstore/test/browser/browser_350525.js
+++ b/browser/components/sessionstore/test/browser/browser_350525.js
@@ -92,7 +92,7 @@ function test() {
       is(this.currentURI.spec, testURL, "correct tab was reopened");
       
       // clean up
-      gPrefService.setIntPref("browser.sessionstore.max_tabs_undo", max_tabs_undo);
+      gPrefService.clearUserPref("browser.sessionstore.max_tabs_undo");
       tabbrowser.removeTab(tab);
       finish();
     }, true);
diff --git a/browser/components/sessionstore/test/browser/browser_367052.js b/browser/components/sessionstore/test/browser/browser_367052.js
index 42e2c6ae031d..22150755e6f5 100644
--- a/browser/components/sessionstore/test/browser/browser_367052.js
+++ b/browser/components/sessionstore/test/browser/browser_367052.js
@@ -65,7 +65,7 @@ function test() {
          "The closed blank tab wasn't added to Recently Closed Tabs");
       
       // clean up
-      gPrefService.setIntPref("browser.sessionstore.max_tabs_undo", max_tabs_undo);
+      gPrefService.clearUserPref("browser.sessionstore.max_tabs_undo");
       finish();
     }, true);
   }, true);
diff --git a/browser/components/sessionstore/test/browser/browser_448741.js b/browser/components/sessionstore/test/browser/browser_448741.js
index 71e86c5a9b4f..fab5533ffeae 100644
--- a/browser/components/sessionstore/test/browser/browser_448741.js
+++ b/browser/components/sessionstore/test/browser/browser_448741.js
@@ -45,7 +45,6 @@ function test() {
   
   let uniqueName = "bug 448741";
   let uniqueValue = "as good as unique: " + Date.now();
-  let interval = gPrefService.getIntPref("browser.sessionstore.interval");
   
   // set a unique value on a new, blank tab
   var tab = tabbrowser.addTab();
@@ -87,7 +86,7 @@ function test() {
       // clean up
       tabbrowser.removeTab(tab);
       os.removeObserver(this, aTopic, false);
-      gPrefService.setIntPref("browser.sessionstore.interval", interval);
+      gPrefService.clearUserPref("browser.sessionstore.interval");
       finish();
     }
   };
diff --git a/browser/components/sessionstore/test/browser/browser_454908.js b/browser/components/sessionstore/test/browser/browser_454908.js
index 52fe4c95795a..c91a613319b8 100644
--- a/browser/components/sessionstore/test/browser/browser_454908.js
+++ b/browser/components/sessionstore/test/browser/browser_454908.js
@@ -45,7 +45,6 @@ function test() {
   };
   
   // make sure we do save form data
-  let privacy_level = gPrefService.getIntPref("browser.sessionstore.privacy_level");
   gPrefService.setIntPref("browser.sessionstore.privacy_level", 0);
   
   let testURL = "chrome://mochikit/content/browser/" +
@@ -70,7 +69,7 @@ function test() {
       }
       
       // clean up
-      gPrefService.setIntPref("browser.sessionstore.privacy_level", privacy_level);
+      gPrefService.clearUserPref("browser.sessionstore.privacy_level");
       // undoCloseTab can reuse a single blank tab, so we have to
       // make sure not to close the window when closing our last tab
       if (gBrowser.tabContainer.childNodes.length == 1)
diff --git a/browser/components/sessionstore/test/browser/browser_456342.js b/browser/components/sessionstore/test/browser/browser_456342.js
index d48f77129e61..d1a38f6027a8 100644
--- a/browser/components/sessionstore/test/browser/browser_456342.js
+++ b/browser/components/sessionstore/test/browser/browser_456342.js
@@ -40,7 +40,6 @@ function test() {
   waitForExplicitFinish();
   
   // make sure we do save form data
-  let privacy_level = gPrefService.getIntPref("browser.sessionstore.privacy_level");
   gPrefService.setIntPref("browser.sessionstore.privacy_level", 0);
   
   let testURL = "chrome://mochikit/content/browser/" +
@@ -66,7 +65,7 @@ function test() {
     is(countBad,  0, "Didn't save text for ignored field types");
     
     // clean up
-    gPrefService.setIntPref("browser.sessionstore.privacy_level", privacy_level);
+    gPrefService.clearUserPref("browser.sessionstore.privacy_level");
     finish();
   }, true);
 }
diff --git a/browser/components/sessionstore/test/browser/browser_464199.js b/browser/components/sessionstore/test/browser/browser_464199.js
index 15beb4e28149..c06d18ef5e57 100644
--- a/browser/components/sessionstore/test/browser/browser_464199.js
+++ b/browser/components/sessionstore/test/browser/browser_464199.js
@@ -75,7 +75,6 @@ function test() {
   // open a window and add the above closed tab list
   let newWin = openDialog(location, "_blank", "chrome,all,dialog=no");
   newWin.addEventListener("load", function(aEvent) {
-    let max_tabs_undo = gPrefService.getIntPref("browser.sessionstore.max_tabs_undo");
     gPrefService.setIntPref("browser.sessionstore.max_tabs_undo",
                             test_state.windows[0]._closedTabs.length);
     ss.setWindowState(newWin, JSON.stringify(test_state), true);
@@ -103,7 +102,7 @@ function test() {
     
     // clean up
     newWin.close();
-    gPrefService.setIntPref("browser.sessionstore.max_tabs_undo", max_tabs_undo);
+    gPrefService.clearUserPref("browser.sessionstore.max_tabs_undo");
     finish();
   }, false);
 }