diff --git a/pillarsdk/nodes.py b/pillarsdk/nodes.py
index 016c902..43cbdc2 100755
--- a/pillarsdk/nodes.py
+++ b/pillarsdk/nodes.py
@@ -41,13 +41,7 @@ class Node(List, Find, Create, Post, Update, Delete, Replace):
         api = api or self.api
         attributes = attributes or self.to_dict()
         etag = attributes['_etag']
-        attributes.pop('_id')
-        attributes.pop('_etag')
-        attributes.pop('_created')
-        attributes.pop('_updated')
-        attributes.pop('_links', None)
-        attributes.pop('_deleted', None)
-        attributes.pop('allowed_methods')
+        attributes = utils.remove_private_keys(attributes)
         attributes = utils.remove_none_attributes(attributes)
 
         url = utils.join_url(self.path, str(self['_id']))
diff --git a/pillarsdk/utils.py b/pillarsdk/utils.py
index 75c3921..7c1fe5e 100644
--- a/pillarsdk/utils.py
+++ b/pillarsdk/utils.py
@@ -1,3 +1,4 @@
+import copy
 import json
 import re
 import sys
@@ -162,6 +163,24 @@ def remove_none_attributes(attributes):
         return attributes
 
 
+def remove_private_keys(document):
+    """Removes any key that starts with an underscore, returns result as new
+    dictionary.
+    """
+
+    doc_copy = copy.deepcopy(document)
+    for key in list(doc_copy.keys()):
+        if key.startswith('_'):
+            del doc_copy[key]
+
+    try:
+        del doc_copy['allowed_methods']
+    except KeyError:
+        pass
+
+    return doc_copy
+
+
 def download_to_file(url, filename, chunk_size=10 * 1024):
     """Downloads a file via HTTP(S) directly to the filesystem."""