diff --git a/Lib/idlelib/PyShell.py b/Lib/idlelib/PyShell.py
index dcce2eb..d15034f 100644
--- a/Lib/idlelib/PyShell.py
+++ b/Lib/idlelib/PyShell.py
@@ -201,18 +201,18 @@
         breaks = self.breakpoints
         filename = self.io.filename
         try:
-            lines = open(self.breakpointPath,"r").readlines()
+            with open(self.breakpointPath, "r") as fp:
+                lines = fp.readlines()
         except IOError:
             lines = []
-        new_file = open(self.breakpointPath,"w")
-        for line in lines:
-            if not line.startswith(filename + '='):
-                new_file.write(line)
-        self.update_breakpoints()
-        breaks = self.breakpoints
-        if breaks:
-            new_file.write(filename + '=' + str(breaks) + '\n')
-        new_file.close()
+        with open(self.breakpointPath, "w") as new_file:
+            for line in lines:
+                if not line.startswith(filename + '='):
+                    new_file.write(line)
+            self.update_breakpoints()
+            breaks = self.breakpoints
+            if breaks:
+                new_file.write(filename + '=' + str(breaks) + '\n')
 
     def restore_file_breaks(self):
         self.text.update()   # this enables setting "BREAK" tags to be visible
@@ -220,7 +220,8 @@
         if filename is None:
             return
         if os.path.isfile(self.breakpointPath):
-            lines = open(self.breakpointPath,"r").readlines()
+            with open(self.breakpointPath, "r") as fp:
+                lines = fp.readlines()
             for line in lines:
                 if line.startswith(filename + '='):
                     breakpoint_linenumbers = eval(line[len(filename)+1:])
@@ -571,7 +572,8 @@
     def execfile(self, filename, source=None):
         "Execute an existing file"
         if source is None:
-            source = open(filename, "r").read()
+            with open(filename, "r") as fp:
+                source = fp.read()
         try:
             code = compile(source, filename, "exec")
         except (OverflowError, SyntaxError):
diff --git a/Lib/idlelib/ScriptBinding.py b/Lib/idlelib/ScriptBinding.py
index 90972b5..915e56e 100644
--- a/Lib/idlelib/ScriptBinding.py
+++ b/Lib/idlelib/ScriptBinding.py
@@ -67,25 +67,20 @@
 
     def tabnanny(self, filename):
         # XXX: tabnanny should work on binary files as well
-        with open(filename, 'r', encoding='iso-8859-1') as f:
-            two_lines = f.readline() + f.readline()
-        encoding = IOBinding.coding_spec(two_lines)
-        if not encoding:
-            encoding = 'utf-8'
-        f = open(filename, 'r', encoding=encoding)
-        try:
-            tabnanny.process_tokens(tokenize.generate_tokens(f.readline))
-        except tokenize.TokenError as msg:
-            msgtxt, (lineno, start) = msg
-            self.editwin.gotoline(lineno)
-            self.errorbox("Tabnanny Tokenizing Error",
-                          "Token Error: %s" % msgtxt)
-            return False
-        except tabnanny.NannyNag as nag:
-            # The error messages from tabnanny are too confusing...
-            self.editwin.gotoline(nag.get_lineno())
-            self.errorbox("Tab/space error", indent_message)
-            return False
+        with tokenize.open(filename) as f:
+            try:
+                tabnanny.process_tokens(tokenize.generate_tokens(f.readline))
+            except tokenize.TokenError as msg:
+                msgtxt, (lineno, start) = msg
+                self.editwin.gotoline(lineno)
+                self.errorbox("Tabnanny Tokenizing Error",
+                              "Token Error: %s" % msgtxt)
+                return False
+            except tabnanny.NannyNag as nag:
+                # The error messages from tabnanny are too confusing...
+                self.editwin.gotoline(nag.get_lineno())
+                self.errorbox("Tab/space error", indent_message)
+                return False
         return True
 
     def checksyntax(self, filename):