diff --git a/idea.whatwg.org/index.html b/idea.whatwg.org/index.html
index 7e502848a..8341cfb24 100644
--- a/idea.whatwg.org/index.html
+++ b/idea.whatwg.org/index.html
@@ -41,3 +41,8 @@ <h2>Ideas</h2>
 <footer>
  <p><small>Copyright © 2018 WHATWG (Apple, Google, Mozilla, Microsoft). This work is licensed under a <a rel="license" href="https://creativecommons.org/licenses/by/4.0/">Creative Commons Attribution 4.0 International License</a>.</small></p>
 </footer>
+
+<script>
+"use strict";
+navigator.serviceWorker.register("/service-worker.js");
+</script>
diff --git a/idea.whatwg.org/service-worker.js b/idea.whatwg.org/service-worker.js
index f90c26930..4c84ed259 100644
--- a/idea.whatwg.org/service-worker.js
+++ b/idea.whatwg.org/service-worker.js
@@ -1,11 +1,2 @@
 "use strict";
-
-self.cacheKey = "v1";
-self.toCache = [
-  "/",
-  "https://whatwg.org/style/shared.css",
-  "https://whatwg.org/style/subpages.css",
-  "https://resources.whatwg.org/logo.svg"
-];
-
 importScripts("https://resources.whatwg.org/website-service-worker.js");
diff --git a/resources.whatwg.org/website-service-worker.js b/resources.whatwg.org/website-service-worker.js
index ede846092..3df8f5777 100644
--- a/resources.whatwg.org/website-service-worker.js
+++ b/resources.whatwg.org/website-service-worker.js
@@ -1,27 +1,30 @@
 "use strict";
 /* USAGE:
 
-  self.cacheKey = "v1";
-  self.toCache = "...";
+  // Optional:
+  self.cacheKey = "v3";
+  self.toCache = ["..."];
+
+  // Then:
   importScripts("https://resources.whatwg.org/website-service-worker.js");
 
 */
 
-const cacheKey = "v1";
-const toCache = [
+const cacheKeyToUse = "v2_" + (self.cacheKey || "v0");
+const everythingToCache = [
   "/",
   "https://whatwg.org/style/shared.css",
   "https://whatwg.org/style/subpages.css",
   "https://resources.whatwg.org/logo.svg"
-];
+].concat(self.toCache || []);
 
 self.oninstall = e => {
-  e.waitUntil(caches.open(self.cacheKey).then(cache => cache.addAll(self.toCache)));
+  e.waitUntil(caches.open(cacheKeyToUse).then(cache => cache.addAll(everythingToCache)));
 };
 
 self.onactivate = e => {
   e.waitUntil(caches.keys().then(keys => {
-    return Promise.all(keys.filter(key => key !== self.cacheKey).map(key => caches.delete(key)));
+    return Promise.all(keys.filter(key => key !== cacheKeyToUse).map(key => caches.delete(key)));
   }));
 };
 
@@ -57,5 +60,5 @@ function refreshCacheFromNetworkResponse(req, res) {
 
   const resForCache = res.clone();
 
-  return caches.open(self.cacheKey).then(cache => cache.put(req, resForCache));
+  return caches.open(cacheKeyToUse).then(cache => cache.put(req, resForCache));
 }
diff --git a/spec.whatwg.org/service-worker.js b/spec.whatwg.org/service-worker.js
index f90c26930..4c84ed259 100644
--- a/spec.whatwg.org/service-worker.js
+++ b/spec.whatwg.org/service-worker.js
@@ -1,11 +1,2 @@
 "use strict";
-
-self.cacheKey = "v1";
-self.toCache = [
-  "/",
-  "https://whatwg.org/style/shared.css",
-  "https://whatwg.org/style/subpages.css",
-  "https://resources.whatwg.org/logo.svg"
-];
-
 importScripts("https://resources.whatwg.org/website-service-worker.js");
diff --git a/whatwg.org/service-worker.js b/whatwg.org/service-worker.js
index 6573c4bec..4e7f311b5 100644
--- a/whatwg.org/service-worker.js
+++ b/whatwg.org/service-worker.js
@@ -1,10 +1,6 @@
 "use strict";
 
-self.cacheKey = "v1";
 self.toCache = [
-  "/",
-  "/shared.css",
-  "/subpages.css",
   "/img/arrow.svg",
   "/img/bird-webpage.svg",
   "/img/checker.svg",
@@ -21,8 +17,7 @@ self.toCache = [
   "/code-of-conduct",
   "/working-mode",
   "/sg-agreement",
-  "/sg-policy",
-  "https://resources.whatwg.org/logo.svg"
+  "/sg-policy"
 ];
 
 importScripts("https://resources.whatwg.org/website-service-worker.js");