diff --git a/secretpy/cmdecorators/lowercase.py b/secretpy/cmdecorators/lowercase.py
index 6af62e1..120df5d 100755
--- a/secretpy/cmdecorators/lowercase.py
+++ b/secretpy/cmdecorators/lowercase.py
@@ -7,7 +7,7 @@
 class LowerCase(AbstractMachineDecorator):
 
     def encrypt(self, text):
-        return self._machine.encrypt(text.lower())
+        return self._machine.encrypt(text).lower()
 
     def decrypt(self, text):
-        return self._machine.decrypt(text.lower())
+        return self._machine.decrypt(text).lower()
diff --git a/secretpy/cmdecorators/save_all.py b/secretpy/cmdecorators/save_all.py
index c9900a0..7177a5b 100755
--- a/secretpy/cmdecorators/save_all.py
+++ b/secretpy/cmdecorators/save_all.py
@@ -14,21 +14,18 @@ def decrypt(self, text):
 
     def __crypt(self, text, func):
         # make lower case and save indexes
-        upcases = [i for i, char in enumerate(text) if char.isupper()]
-        txt = list(text)
-        for i in upcases:
-            txt[i] = txt[i].lower()
+        upcases = [i for i, c in enumerate(text) if c.isupper()]
+        txt = text.lower()
 
-        # remove non-alphabet characters and save indexes
+        # prepare alphabet
         alphabet = self._machine.get_alphabet()
-        coords = {c: i for i, letters in enumerate(alphabet) for c in letters}
-        chars = [i for i, char in enumerate(txt) if char not in coords]
-        for i in reversed(chars):
-            del txt[i]
+        alpha = {c: 1 for letters in alphabet for c in letters}
+
+        # save indexes of non-alphabet characters
+        chars = [i for i, c in enumerate(txt) if c not in alpha]
 
         # execute function
-        res = func("".join(txt))
-        res = list(res)
+        res = list(func(txt))
 
         # restore non-alphabet characters
         for i in chars:
diff --git a/secretpy/cmdecorators/uppercase.py b/secretpy/cmdecorators/uppercase.py
index ed92f7e..bc3034a 100755
--- a/secretpy/cmdecorators/uppercase.py
+++ b/secretpy/cmdecorators/uppercase.py
@@ -7,9 +7,7 @@
 class UpperCase(AbstractMachineDecorator):
 
     def encrypt(self, text):
-        res = self._machine.encrypt(text.lower())
-        return res.upper()
+        return self._machine.encrypt(text).upper()
 
     def decrypt(self, text):
-        res = self._machine.decrypt(text.lower())
-        return res.upper()
+        return self._machine.decrypt(text).upper()
diff --git a/secretpy/cryptmachine.py b/secretpy/cryptmachine.py
index 4ed007d..9be3185 100755
--- a/secretpy/cryptmachine.py
+++ b/secretpy/cryptmachine.py
@@ -34,5 +34,5 @@ def __crypt(self, text, func):
         # prepare alphabet
         alpha = {c: 1 for letters in self.__alphabet for c in letters}
         # filter text by alphabet
-        text = "".join(filter(lambda c: c in alpha, text.lower()))
-        return func(text, self.__key, self.__alphabet)
+        txt = "".join(filter(lambda c: c in alpha, text.lower()))
+        return func(txt, self.__key, self.__alphabet)