diff --git a/c-historico/handler.cr b/c-historico/handler.cr
index 35b6cba..5c91bd3 100644
--- a/c-historico/handler.cr
+++ b/c-historico/handler.cr
@@ -70,7 +70,7 @@ class Handler
     # Remove diacritics, turn lowercase
     normalized = s.unicode_normalize(:nfkd).chars
     normalized.reject! { |character|
-      !character.ascii_letter?
+      !character.ascii?
     }.join("").downcase
   end