diff --git a/src/mu-str.c b/src/mu-str.c
index d88e9647..6a04fd45 100644
--- a/src/mu-str.c
+++ b/src/mu-str.c
@@ -534,6 +534,9 @@ char*
 mu_str_asciify_in_place (char *buf)
 {
 	char *c;
+
+	g_return_val_if_fail (buf, NULL);
+
 	for (c = buf; c && *c; ++c)
 		if (!isascii(*c))
 			c[0] = '.';
@@ -541,6 +544,23 @@ mu_str_asciify_in_place (char *buf)
 	return buf;
 }
 
+char*
+mu_str_utf8ify (const char *buf)
+{
+	char *utf8;
+
+	g_return_val_if_fail (buf, NULL);
+
+	utf8 = g_strdup (buf);
+
+	if (!g_utf8_validate (buf, -1, NULL))
+	    mu_str_asciify_in_place (utf8);
+
+	return utf8;
+}
+
+
+
 gchar*
 mu_str_convert_to_utf8 (const char* buffer, const char *charset)
 {
diff --git a/src/mu-str.h b/src/mu-str.h
index e0c30bdc..92af523f 100644
--- a/src/mu-str.h
+++ b/src/mu-str.h
@@ -220,6 +220,17 @@ char* mu_str_escape_c_literal (const gchar* str, gboolean in_quotes)
 char* mu_str_asciify_in_place (char *buf);
 
 
+/**
+ * turn string in buf into valid utf8. If this string is not valid
+ * utf8 already, the function massages the offending characters.
+ *
+ * @param buf a buffer to utf8ify
+ *
+ * @return a newly allocated utf8 string
+ */
+char* mu_str_utf8ify (const char *buf);
+
+
 /**
  * convert a string in a certain charset into utf8
  *