diff --git a/src/calibre/ebooks/rtf2xml/replace_illegals.py b/src/calibre/ebooks/rtf2xml/replace_illegals.py
index 901cdd289d..9c5c1ef0e9 100755
--- a/src/calibre/ebooks/rtf2xml/replace_illegals.py
+++ b/src/calibre/ebooks/rtf2xml/replace_illegals.py
@@ -16,7 +16,10 @@
 #                                                                       #
 #########################################################################
 import os, tempfile
+
 from calibre.ebooks.rtf2xml import copy
+from calibre.utils.cleantext import clean_ascii_chars
+
 class ReplaceIllegals:
     """
     reaplace illegal lower ascii characters
@@ -30,21 +33,14 @@ class ReplaceIllegals:
         self.__copy = copy
         self.__run_level = run_level
         self.__write_to = tempfile.mktemp()
+
     def replace_illegals(self):
         """
         """
-        nums = [0, 1, 2, 3, 4, 5, 6, 7, 8,  11,  13, 14, 15, 16, 17, 18, 19]
-        read_obj = open(self.__file, 'r')
-        write_obj = open(self.__write_to, 'w')
-        line_to_read = 1
-        while line_to_read:
-            line_to_read = read_obj.readline()
-            line = line_to_read
-            for num in nums:
-                line = line.replace(chr(num), '')
-            write_obj.write(line)
-        read_obj.close()
-        write_obj.close()
+        with open(self.__file, 'r') as read_obj, \
+            open(self.__write_to, 'w') as write_obj:
+            for line in read_obj:
+                write_obj.write(clean_ascii_chars(line))
         copy_obj = copy.Copy()
         if self.__copy:
             copy_obj.copy_file(self.__write_to, "replace_illegals.data")