diff --git a/tools/test_corpus_engine.sh b/tools/test_corpus_engine.sh
index 827607a6..4a113660 100755
--- a/tools/test_corpus_engine.sh
+++ b/tools/test_corpus_engine.sh
@@ -839,8 +839,9 @@ echo "$out" | grep -q 'labels the Thought-only effects lab with retired particul
   echo "$out"
   fail=1
 }
-sed -i 's/Effects lab: dust and liquid/Effects lab: Thought routes and pools/' \
+sed -i.bak 's/Effects lab: dust and liquid/Effects lab: Thought routes and pools/' \
   "$root/wiki/SUMMARY.md"
+rm "$root/wiki/SUMMARY.md.bak"
 
 cat > "$root/wiki/process/exposure-knowledge.md" <<'EOF'
 # Exposure knowledge