diff --git a/BLcourse2.3/convert-to-ipynb.sh b/BLcourse2.3/convert-to-ipynb.sh
index 82f9566c576371f7a70f8d33f0a4866955adb8db..2c58472d0b6688a4c1fc37c31371aa1905c9c5c4 100755
--- a/BLcourse2.3/convert-to-ipynb.sh
+++ b/BLcourse2.3/convert-to-ipynb.sh
@@ -1,5 +1,10 @@
 #!/bin/sh
 
+# Remove plots etc, but keep random cell IDs. We need this b/c we use jupytext
+# --update below.
+nbstripout --keep-id *.ipynb
+
 for fn in 0*dim.py; do
+    # --update keeps call IDs -> smaller diffs
     jupytext --to ipynb --update $fn
 done
diff --git a/BLcourse2.3/requirements.txt b/BLcourse2.3/requirements.txt
index c1b364c4066690d63c0b461774fb5d1bd4436255..2a0a563ac5d2dd8a06ab84bdc9d5cb6ad6445ea6 100644
--- a/BLcourse2.3/requirements.txt
+++ b/BLcourse2.3/requirements.txt
@@ -30,4 +30,10 @@ jupyter
 # or Jupyter notebook is also fine
 ##notebook
 
+# ----------------------------------------------------------------------------
+# dev
+# ----------------------------------------------------------------------------
+
+nbstripout
+
 # vim:syn=sh