diff --git a/odoo/tools/mail.py b/odoo/tools/mail.py
index 0f6a8c86b30..b5477caa3d3 100644
--- a/odoo/tools/mail.py
+++ b/odoo/tools/mail.py
@@ -76,7 +76,7 @@ class _Cleaner(clean.Cleaner):
     def __call__(self, doc):
         # perform quote detection before cleaning and class removal
         for el in doc.iter(tag=etree.Element):
-            self.tag_quote(el)
+            tag_quote(el)
 
         super(_Cleaner, self).__call__(doc)
 
@@ -90,74 +90,6 @@ class _Cleaner(clean.Cleaner):
             for el in doc.iter(tag=etree.Element):
                 self.parse_style(el)
 
-    def tag_quote(self, el):
-        def _create_new_node(tag, text, tail=None, attrs=None):
-            new_node = etree.Element(tag)
-            new_node.text = text
-            new_node.tail = tail
-            if attrs:
-                for key, val in attrs.items():
-                    new_node.set(key, val)
-            return new_node
-
-        def _tag_matching_regex_in_text(regex, node, tag='span', attrs=None):
-            text = node.text or ''
-            if not re.search(regex, text):
-                return
-
-            child_node = None
-            idx, node_idx = 0, 0
-            for item in re.finditer(regex, text):
-                new_node = _create_new_node(tag, text[item.start():item.end()], None, attrs)
-                if child_node is None:
-                    node.text = text[idx:item.start()]
-                    new_node.tail = text[item.end():]
-                    node.insert(node_idx, new_node)
-                else:
-                    child_node.tail = text[idx:item.start()]
-                    new_node.tail = text[item.end():]
-                    node.insert(node_idx, new_node)
-                child_node = new_node
-                idx = item.end()
-                node_idx = node_idx + 1
-
-        el_class = el.get('class', '') or ''
-        el_id = el.get('id', '') or ''
-
-        # gmail or yahoo // # outlook, html // # msoffice
-        if 'gmail_extra' in el_class or \
-                'divRplyFwdMsg' in el_id or \
-                ('SkyDrivePlaceholder' in el_class or 'SkyDrivePlaceholder' in el_class):
-            el.set('data-o-mail-quote', '1')
-            if el.getparent() is not None:
-                el.getparent().set('data-o-mail-quote-container', '1')
-
-        if (el.tag == 'hr' and ('stopSpelling' in el_class or 'stopSpelling' in el_id)) or \
-           'yahoo_quoted' in el_class:
-            # Quote all elements after this one
-            el.set('data-o-mail-quote', '1')
-            for sibling in el.itersiblings(preceding=False):
-                sibling.set('data-o-mail-quote', '1')
-
-        # html signature (-- <br />blah)
-        signature_begin = re.compile(r"((?:(?:^|\n)[-]{2}[\s]?$))")
-        if el.text and el.find('br') is not None and re.search(signature_begin, el.text):
-            el.set('data-o-mail-quote', '1')
-            if el.getparent() is not None:
-                el.getparent().set('data-o-mail-quote-container', '1')
-
-        # text-based quotes (>, >>) and signatures (-- Signature)
-        text_complete_regex = re.compile(r"((?:\n[>]+[^\n\r]*)+|(?:(?:^|\n)[-]{2}[\s]?[\r\n]{1,2}[\s\S]+))")
-        if not el.get('data-o-mail-quote'):
-            _tag_matching_regex_in_text(text_complete_regex, el, 'span', {'data-o-mail-quote': '1'})
-
-        if el.tag == 'blockquote':
-            # remove single node
-            el.set('data-o-mail-quote-node', '1')
-            el.set('data-o-mail-quote', '1')
-        if el.getparent() is not None and (el.getparent().get('data-o-mail-quote') or el.getparent().get('data-o-mail-quote-container')) and not el.getparent().get('data-o-mail-quote-node'):
-            el.set('data-o-mail-quote', '1')
-
     def strip_class(self, el):
         if el.attrib.get('class'):
             del el.attrib['class']
@@ -177,6 +109,75 @@ class _Cleaner(clean.Cleaner):
                 del el.attrib['style']
 
 
+def tag_quote(el):
+    def _create_new_node(tag, text, tail=None, attrs=None):
+        new_node = etree.Element(tag)
+        new_node.text = text
+        new_node.tail = tail
+        if attrs:
+            for key, val in attrs.items():
+                new_node.set(key, val)
+        return new_node
+
+    def _tag_matching_regex_in_text(regex, node, tag='span', attrs=None):
+        text = node.text or ''
+        if not re.search(regex, text):
+            return
+
+        child_node = None
+        idx, node_idx = 0, 0
+        for item in re.finditer(regex, text):
+            new_node = _create_new_node(tag, text[item.start():item.end()], None, attrs)
+            if child_node is None:
+                node.text = text[idx:item.start()]
+                new_node.tail = text[item.end():]
+                node.insert(node_idx, new_node)
+            else:
+                child_node.tail = text[idx:item.start()]
+                new_node.tail = text[item.end():]
+                node.insert(node_idx, new_node)
+            child_node = new_node
+            idx = item.end()
+            node_idx = node_idx + 1
+
+    el_class = el.get('class', '') or ''
+    el_id = el.get('id', '') or ''
+
+    # gmail or yahoo // # outlook, html // # msoffice
+    if 'gmail_extra' in el_class or \
+            'divRplyFwdMsg' in el_id or \
+            ('SkyDrivePlaceholder' in el_class or 'SkyDrivePlaceholder' in el_class):
+        el.set('data-o-mail-quote', '1')
+        if el.getparent() is not None:
+            el.getparent().set('data-o-mail-quote-container', '1')
+
+    if (el.tag == 'hr' and ('stopSpelling' in el_class or 'stopSpelling' in el_id)) or \
+       'yahoo_quoted' in el_class:
+        # Quote all elements after this one
+        el.set('data-o-mail-quote', '1')
+        for sibling in el.itersiblings(preceding=False):
+            sibling.set('data-o-mail-quote', '1')
+
+    # html signature (-- <br />blah)
+    signature_begin = re.compile(r"((?:(?:^|\n)[-]{2}[\s]?$))")
+    if el.text and el.find('br') is not None and re.search(signature_begin, el.text):
+        el.set('data-o-mail-quote', '1')
+        if el.getparent() is not None:
+            el.getparent().set('data-o-mail-quote-container', '1')
+
+    # text-based quotes (>, >>) and signatures (-- Signature)
+    text_complete_regex = re.compile(r"((?:\n[>]+[^\n\r]*)+|(?:(?:^|\n)[-]{2}[\s]?[\r\n]{1,2}[\s\S]+))")
+    if not el.get('data-o-mail-quote'):
+        _tag_matching_regex_in_text(text_complete_regex, el, 'span', {'data-o-mail-quote': '1'})
+
+    if el.tag == 'blockquote':
+        # remove single node
+        el.set('data-o-mail-quote-node', '1')
+        el.set('data-o-mail-quote', '1')
+    if el.getparent() is not None and (el.getparent().get('data-o-mail-quote') or el.getparent().get('data-o-mail-quote-container')) and not el.getparent().get('data-o-mail-quote-node'):
+        el.set('data-o-mail-quote', '1')
+
+
 def html_sanitize(src, silent=True, sanitize_tags=True, sanitize_attributes=False, sanitize_style=False, sanitize_form=True, strip_style=False, strip_classes=False):
     if not src:
         return src