diff --git a/paper/concat_code.sh b/paper/concat_code.sh
index d4a72c1..3ff905d 100755
--- a/paper/concat_code.sh
+++ b/paper/concat_code.sh
@@ -21,8 +21,10 @@ add_file() {
     # Add section header and code listing (no language-specific highlighting)
     echo "\\subsection{${escaped_path}}" >> "$OUTPUT_FILE"
     echo "\\begin{lstlisting}[caption={${escaped_path}}]" >> "$OUTPUT_FILE"
-    # Sanitize UTF-8: convert to ASCII with transliteration to avoid invalid UTF-8 bytes
-    iconv -f UTF-8 -t ASCII//TRANSLIT "$filepath" >> "$OUTPUT_FILE" 2>/dev/null || cat "$filepath" >> "$OUTPUT_FILE"
+    # Convert to ASCII: transliterate what's possible, drop the rest
+    # LC_ALL=C forces ASCII locale for consistent behavior across environments
+    LC_ALL=C iconv -f UTF-8 -t ASCII//TRANSLIT//IGNORE "$filepath" 2>/dev/null >> "$OUTPUT_FILE" || \
+        LC_ALL=C tr -cd '\11\12\15\40-\176' < "$filepath" >> "$OUTPUT_FILE"
     echo "" >> "$OUTPUT_FILE"
     echo "\\end{lstlisting}" >> "$OUTPUT_FILE"
     echo "" >> "$OUTPUT_FILE"