diff --git a/encode.c b/encode.c
index d821a54df..66ab1616c 100644
--- a/encode.c
+++ b/encode.c
@@ -483,9 +483,7 @@ PyImaging_ZipEncoderNew(PyObject* self, PyObject* args)
                           &dictionary, &dictionary_size))
         return NULL;
 
-    /* Copy to avoid referencing Python's memory, but there's no mechanism to
-       free this memory later, so this function (and several others here)
-       leaks. */
+    /* Copy to avoid referencing Python's memory */
     if (dictionary && dictionary_size > 0) {
         /* malloc check ok, size comes from PyArg_ParseTuple */
         char* p = malloc(dictionary_size);
@@ -504,6 +502,7 @@ PyImaging_ZipEncoderNew(PyObject* self, PyObject* args)
         return NULL;
 
     encoder->encode = ImagingZipEncode;
+    encoder->cleanup = ImagingZipEncodeCleanup;
 
     if (rawmode[0] == 'P')
         /* disable filtering */
@@ -638,6 +637,7 @@ PyImaging_JpegEncoderNew(PyObject* self, PyObject* args)
     if (get_packer(encoder, mode, rawmode) < 0)
         return NULL;
 
+    // Freed in JpegEncode, Case 5
     qarrays = get_qtables_arrays(qtables, &qtablesLen);
 
     if (extra && extra_size > 0) {
diff --git a/libImaging/Imaging.h b/libImaging/Imaging.h
index bbef0440d..aa4009889 100644
--- a/libImaging/Imaging.h
+++ b/libImaging/Imaging.h
@@ -474,6 +474,7 @@ extern int ImagingZipDecode(Imaging im, ImagingCodecState state,
 			    UINT8* buffer, int bytes);
 extern int ImagingZipEncode(Imaging im, ImagingCodecState state,
 			    UINT8* buffer, int bytes);
+extern int ImagingZipEncodeCleanup(ImagingCodecState state);
 #endif
 
 typedef void (*ImagingShuffler)(UINT8* out, const UINT8* in, int pixels);
diff --git a/libImaging/ZipEncode.c b/libImaging/ZipEncode.c
index 7f50be9ed..4a431fb33 100644
--- a/libImaging/ZipEncode.c
+++ b/libImaging/ZipEncode.c
@@ -348,6 +348,24 @@ ImagingZipEncode(Imaging im, ImagingCodecState state, UINT8* buf, int bytes)
     return -1;
 }
 
+/* -------------------------------------------------------------------- */
+/* Cleanup                                                              */
+/* -------------------------------------------------------------------- */
+
+int
+ImagingZipEncodeCleanup(ImagingCodecState state) {
+    ZIPSTATE* context = (ZIPSTATE*) state->context;
+
+    if (context->dictionary) {
+        free (context->dictionary);
+        context->dictionary = NULL;
+    }
+
+    return -1;
+}
+
+
+
 const char*
 ImagingZipVersion(void)
 {