diff --git a/twython/twython.py b/twython/twython.py
index 4bd2fa7..bc2904d 100644
--- a/twython/twython.py
+++ b/twython/twython.py
@@ -13,7 +13,6 @@ __version__ = "1.5.2"
 
 import urllib
 import re
-import inspect
 import time
 
 import requests
@@ -49,21 +48,6 @@ except ImportError:
             # Seriously wtf is wrong with you if you get this Exception.
             raise Exception("Twython requires the simplejson library (or Python 2.6) to work. http://www.undefined.org/python/")
 
-# Try and gauge the old OAuth2 library spec. Versions 1.5 and greater no longer have the callback
-# url as part of the request object; older versions we need to patch for Python 2.5... ugh. ;P
-OAUTH_CALLBACK_IN_URL = False
-OAUTH_LIB_SUPPORTS_CALLBACK = False
-if not hasattr(oauth, '_version') or float(oauth._version.manual_verstr) <= 1.4:
-    OAUTH_CLIENT_INSPECTION = inspect.getargspec(oauth.Client.request)
-    try:
-        OAUTH_LIB_SUPPORTS_CALLBACK = 'callback_url' in OAUTH_CLIENT_INSPECTION.args
-    except AttributeError:
-        # Python 2.5 doesn't return named tuples, so don't look for an args section specifically.
-        OAUTH_LIB_SUPPORTS_CALLBACK = 'callback_url' in OAUTH_CLIENT_INSPECTION
-else:
-    OAUTH_CALLBACK_IN_URL = True
-
-
 class TwythonError(AttributeError):
     """
         Generic error class, catch-all for most Twython issues.
@@ -238,10 +222,12 @@ class Twython(object):
 
             Returns an authorization URL for a user to hit.
         """
-        callback_url = self.callback_url or 'oob'
+        callback_url = self.callback_url
 
         request_args = {}
-        request_args['oauth_callback'] = callback_url
+        if callback_url:
+            request_args['oauth_callback'] = callback_url
+            
         method = 'get'
 
         func = getattr(self.client, method)
@@ -256,17 +242,12 @@ class Twython(object):
 
         oauth_callback_confirmed = request_tokens.get('oauth_callback_confirmed') == 'true'
 
-        if not OAUTH_LIB_SUPPORTS_CALLBACK and callback_url != 'oob' and oauth_callback_confirmed:
-            import warnings
-            warnings.warn("oauth2 library doesn't support OAuth 1.0a type callback, but remote requires it")
-            oauth_callback_confirmed = False
-
         auth_url_params = {
             'oauth_token': request_tokens['oauth_token'],
         }
 
-        # Use old-style callback argument
-        if OAUTH_CALLBACK_IN_URL or (callback_url != 'oob' and not oauth_callback_confirmed):
+        # Use old-style callback argument if server didn't accept new-style
+        if callback_url and not oauth_callback_confirmed:
             auth_url_params['oauth_callback'] = callback_url
 
         request_tokens['auth_url'] = self.authenticate_url + '?' + urllib.urlencode(auth_url_params)