diff --git a/CHANGES.rst b/CHANGES.rst
index fd4f63dd93..9afe7e6e0a 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -10,6 +10,9 @@ https://zope.readthedocs.io/en/2.13/CHANGES.html
 4.4.4 (unreleased)
 ------------------
 
+- Decrease cookie size for copy/paste clipboard cookie
+  (`#854 <https://github.com/zopefoundation/Zope/issues/854>`_)
+
 - Fix ``default`` keyword handling in page templates
   (`#846 <https://github.com/zopefoundation/Zope/issues/846>`_)
 
diff --git a/src/OFS/CopySupport.py b/src/OFS/CopySupport.py
index 09003eccdd..ef77849c81 100644
--- a/src/OFS/CopySupport.py
+++ b/src/OFS/CopySupport.py
@@ -23,8 +23,6 @@
 from zlib import decompressobj
 
 import six
-from six.moves.urllib.parse import quote
-from six.moves.urllib.parse import unquote
 
 import transaction
 from AccessControl import ClassSecurityInfo
@@ -56,6 +54,14 @@
 from zope.lifecycleevent import ObjectMovedEvent
 
 
+try:
+    from base64 import decodebytes
+    from base64 import encodebytes
+except ImportError:  # Python 2
+    from base64 import decodestring as decodebytes
+    from base64 import encodestring as encodebytes
+
+
 class CopyError(Exception):
     pass
 
@@ -671,10 +677,7 @@ def _cb_encode(d):
     json_bytes = dumps(d).encode('utf-8')
     squashed_bytes = compress(json_bytes, 2)  # -> bytes w/ useful encoding
     # quote for embeding in cookie
-    if six.PY2:
-        return quote(squashed_bytes)
-    else:
-        return quote(squashed_bytes.decode('latin-1'))
+    return encodebytes(squashed_bytes)
 
 
 def _cb_decode(s, maxsize=8192):
@@ -686,11 +689,7 @@ def _cb_decode(s, maxsize=8192):
     Return a list of text IDs.
     """
     dec = decompressobj()
-    if six.PY2:
-        squashed = unquote(s)
-    else:
-        squashed = unquote(s).encode('latin-1')
-    data = dec.decompress(squashed, maxsize)
+    data = dec.decompress(decodebytes(s), maxsize)
     if dec.unconsumed_tail:
         raise ValueError
     json_bytes = data.decode('utf-8')