diff --git a/pysollib/actions.py b/pysollib/actions.py
index 559d728a..6f135482 100644
--- a/pysollib/actions.py
+++ b/pysollib/actions.py
@@ -519,7 +519,8 @@ class PysolMenubar(PysolMenubarTk):
                     text += os.linesep
                 enc = locale.getpreferredencoding()
                 try:
-                    open(fn, 'a').write(text.encode(enc, 'replace'))
+                    with open(fn, 'at') as fh:
+                        fh.write(text.encode(enc, 'replace'))
                 except Exception as err:
                     d = MfxExceptionDialog(
                         self.top, err,
diff --git a/pysollib/cardsetparser.py b/pysollib/cardsetparser.py
index 65a698f1..c96634f7 100644
--- a/pysollib/cardsetparser.py
+++ b/pysollib/cardsetparser.py
@@ -32,7 +32,7 @@ def read_cardset_config(dirname, filename):
 
     This function returns None if any errors occurred.
     """
-    with open(filename, "r") as f:
+    with open(filename, "rt") as f:
         lines = f.readlines()
     lines = [line.strip() for line in lines]
     if not lines[0].startswith("PySol"):
diff --git a/pysollib/htmllib2.py b/pysollib/htmllib2.py
index 1e705ac8..7ff6b2a9 100644
--- a/pysollib/htmllib2.py
+++ b/pysollib/htmllib2.py
@@ -498,19 +498,15 @@ def test(args=None):
         fn = 'test.html'
 
     if fn == '-':
-        f = sys.stdin
+        data = sys.stdin.read()
     else:
         try:
-            f = open(fn, 'r')
+            with open(fn, 'rt') as fh:
+                data = fh.read()
         except IOError as msg:
             print(fn, ":", msg)
             sys.exit(1)
 
-    data = f.read()
-
-    if f is not sys.stdin:
-        f.close()
-
     if silent:
         f = formatter.NullFormatter()
     else:
diff --git a/pysollib/mfxutil.py b/pysollib/mfxutil.py
index a8b48365..b5b27ad4 100644
--- a/pysollib/mfxutil.py
+++ b/pysollib/mfxutil.py
@@ -285,30 +285,23 @@ class KwStruct:
 # ************************************************************************
 
 def pickle(obj, filename, protocol=0):
-    f = None
     try:
-        f = open(filename, "wb")
-        Pickler(f, protocol).dump(obj)
-        f.close()
-        f = None
+        with open(filename, "wb") as fh:
+            Pickler(fh, protocol).dump(obj)
         # print "Pickled", filename
     finally:
-        if f:
-            f.close()
+        pass
 
 
 def unpickle(filename):
-    f, obj = None, None
+    obj = None
     try:
-        f = open(filename, "rb")
-        x = Unpickler(f).load()
-        f.close()
-        f = None
+        with open(filename, "rb") as fh:
+            x = Unpickler(fh).load()
         obj = x
         # print "Unpickled", filename
     finally:
-        if f:
-            f.close()
+        pass
     return obj
 
 
diff --git a/pysollib/tile/selectcardset.py b/pysollib/tile/selectcardset.py
index 45b45f41..4f0e55ca 100644
--- a/pysollib/tile/selectcardset.py
+++ b/pysollib/tile/selectcardset.py
@@ -524,9 +524,10 @@ class CardsetInfoDialog(MfxDialog):
         frame.rowconfigure(1, weight=1)
         #
         text = ''
-        f = os.path.join(cardset.dir, "COPYRIGHT")
+        fn = os.path.join(cardset.dir, "COPYRIGHT")
         try:
-            text = open(f).read()
+            with open(fn, "rt") as fh:
+                text = fh.read()
         except Exception:
             pass
         if text:
diff --git a/pysollib/tk/selectcardset.py b/pysollib/tk/selectcardset.py
index 623ed23d..0f0ff27c 100644
--- a/pysollib/tk/selectcardset.py
+++ b/pysollib/tk/selectcardset.py
@@ -487,9 +487,10 @@ class CardsetInfoDialog(MfxDialog):
         frame.rowconfigure(1, weight=1)
         #
         text = ''
-        f = os.path.join(cardset.dir, "COPYRIGHT")
+        fn = os.path.join(cardset.dir, "COPYRIGHT")
         try:
-            text = open(f).read()
+            with open(fn, "rt") as fh:
+                text = fh.read()
         except Exception:
             pass
         if text:
diff --git a/pysollib/ui/tktile/tkhtml.py b/pysollib/ui/tktile/tkhtml.py
index b15b9597..4e31b62d 100644
--- a/pysollib/ui/tktile/tkhtml.py
+++ b/pysollib/ui/tktile/tkhtml.py
@@ -295,7 +295,8 @@ class Base_HTMLViewer:
                 import codecs
                 return codecs.open(url, encoding='utf-8')
             else:
-                return open(url, "rb")
+                with open(url, "rb") as fh:
+                    return fh
         return my_open(url), url
 
     def display(self, url, add=1, relpath=1, xview=0, yview=0):