diff --git a/whelktool/scripts/cleanups/2023/08/lxl-4230-move-more-bad-identifiedby.groovy b/whelktool/scripts/cleanups/2023/08/lxl-4230-move-more-bad-identifiedby.groovy
new file mode 100644
index 0000000000..e52ef2483c
--- /dev/null
+++ b/whelktool/scripts/cleanups/2023/08/lxl-4230-move-more-bad-identifiedby.groovy
@@ -0,0 +1,37 @@
+String where = "collection = 'bib' and data#>>'{@graph,1,identifiedBy}' like '%MTM medietyp%'"
+
+selectBySqlWhere(where) { data ->
+
+    // Find the two relevant identifiers
+    List identifiedBys = asList(data.graph[1].identifiedBy)
+    Map medieTypIdentifier = identifiedBys.find { identifiedBy ->
+        identifiedBy["typeNote"] == "MTM medietyp"
+    }
+    Map medieNummerIdentifier = identifiedBys.find { identifiedBy ->
+        identifiedBy["typeNote"] == "MTM medienummer"
+    }
+    if (medieNummerIdentifier == null || medieTypIdentifier == null || medieTypIdentifier.value == null)
+        return
+
+    // Make sure there's a qualifier list in medieNummerIdentifier to put stuff in
+    if (medieNummerIdentifier.qualifier == null)
+        medieNummerIdentifier.put("qualifier", [])
+    if (! medieNummerIdentifier.qualifier instanceof List)
+        medieNummerIdentifier.put("qualifier", [medieNummerIdentifier.qualifier])
+
+    // Make the switch and drop the "medietyp"
+    List qualifiers = medieNummerIdentifier.qualifier
+    qualifiers.add(medieTypIdentifier.value)
+    identifiedBys.remove(medieTypIdentifier)
+
+    //System.err.println("ID by after change: " + identifiedBys)
+    data.scheduleSave()
+}
+
+private List asList(Object o) {
+    if (o == null)
+        return []
+    if (o instanceof List)
+        return o
+    return [o]
+}