diff --git a/02_production.ipynb b/02_production.ipynb
index f8c7940..e6e39bd 100644
--- a/02_production.ipynb
+++ b/02_production.ipynb
@@ -1156,6 +1156,17 @@
     "<img alt=\"Cleaner widget\" width=\"700\" src=\"images/att_00007.png\">"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#hide\n",
+    "# for idx in cleaner.delete(): cleaner.fns[idx].unlink()\n",
+    "# for idx,cat in cleaner.change(): shutil.move(cleaner.fns[idx], path/cat)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1654,6 +1665,17 @@
     "### Turning your notebook into a real app"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#hide\n",
+    "# !pip install voila\n",
+    "# !jupyter serverextension enable voila --sys-prefix"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1936,18 +1958,6 @@
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
-  },
-  "language_info": {
-   "codemirror_mode": {
-    "name": "ipython",
-    "version": 3
-   },
-   "file_extension": ".py",
-   "mimetype": "text/x-python",
-   "name": "python",
-   "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.7.4"
   }
  },
  "nbformat": 4,
diff --git a/08_collab.ipynb b/08_collab.ipynb
index 6cc4610..5927831 100644
--- a/08_collab.ipynb
+++ b/08_collab.ipynb
@@ -1226,7 +1226,7 @@
     "weight.grad += wd * 2 * weight\n",
     "```\n",
     "\n",
-    "In practice, since `wd` is a parameter that we choose, we can just make it twice as bit, so we don't even need the `*2` in the above equation. To use weight decay in fastai, just pass `wd` in your call to fit:"
+    "In practice, since `wd` is a parameter that we choose, we can just make it twice as big, so we don't even need the `*2` in the above equation. To use weight decay in fastai, just pass `wd` in your call to fit:"
    ]
   },
   {
@@ -2296,18 +2296,6 @@
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
-  },
-  "language_info": {
-   "codemirror_mode": {
-    "name": "ipython",
-    "version": 3
-   },
-   "file_extension": ".py",
-   "mimetype": "text/x-python",
-   "name": "python",
-   "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.7.4"
   }
  },
  "nbformat": 4,
diff --git a/11_midlevel_data.ipynb b/11_midlevel_data.ipynb
index 56e1291..330897a 100644
--- a/11_midlevel_data.ipynb
+++ b/11_midlevel_data.ipynb
@@ -1257,6 +1257,9 @@
   }
  ],
  "metadata": {
+  "jupytext": {
+   "split_at_heading": true
+  },
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
@@ -1272,7 +1275,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.7.2"
+   "version": "3.7.4"
   }
  },
  "nbformat": 4,
diff --git a/clean/02_production.ipynb b/clean/02_production.ipynb
index a544e53..203f14b 100644
--- a/clean/02_production.ipynb
+++ b/clean/02_production.ipynb
@@ -653,6 +653,17 @@
     "cleaner"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#hide\n",
+    "# for idx in cleaner.delete(): cleaner.fns[idx].unlink()\n",
+    "# for idx,cat in cleaner.change(): shutil.move(cleaner.fns[idx], path/cat)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -952,6 +963,17 @@
     "### Turning your notebook into a real app"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#hide\n",
+    "# !pip install voila\n",
+    "# !jupyter serverextension enable voila --sys-prefix"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1053,18 +1075,6 @@
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
-  },
-  "language_info": {
-   "codemirror_mode": {
-    "name": "ipython",
-    "version": 3
-   },
-   "file_extension": ".py",
-   "mimetype": "text/x-python",
-   "name": "python",
-   "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.7.4"
   }
  },
  "nbformat": 4,
diff --git a/clean/08_collab.ipynb b/clean/08_collab.ipynb
index fba96fa..65be45a 100644
--- a/clean/08_collab.ipynb
+++ b/clean/08_collab.ipynb
@@ -1703,18 +1703,6 @@
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
-  },
-  "language_info": {
-   "codemirror_mode": {
-    "name": "ipython",
-    "version": 3
-   },
-   "file_extension": ".py",
-   "mimetype": "text/x-python",
-   "name": "python",
-   "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.7.4"
   }
  },
  "nbformat": 4,
diff --git a/clean/11_midlevel_data.ipynb b/clean/11_midlevel_data.ipynb
index 74d2722..748c04d 100644
--- a/clean/11_midlevel_data.ipynb
+++ b/clean/11_midlevel_data.ipynb
@@ -836,10 +836,25 @@
   }
  ],
  "metadata": {
+  "jupytext": {
+   "split_at_heading": true
+  },
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.4"
   }
  },
  "nbformat": 4,