diff --git a/Patches.md b/Patches.md
index 5ad8b19..7ef6f49 100644
--- a/Patches.md
+++ b/Patches.md
@@ -7,6 +7,7 @@ On the [/cgi-bin/mailman/listinfo/tahoe-dev tahoe-dev mailing list], Zooko sugge
 
 ```
   darcs send -o patch.darcspatch
+  bzip2 patch.darcspatch
   darcs diff -u -p"${PATCHRE}" > patch.diff.txt
 ```
 
@@ -15,6 +16,8 @@ On the [/cgi-bin/mailman/listinfo/tahoe-dev tahoe-dev mailing list], Zooko sugge
 > and send the message (instead of allowing "darcs send" to send the
 > message for them).
 
+> The bzip2 is necessary to prevent various mail software from mangling the patch so it can't be applied.
+
 > The good things about this are:
   * hopefully everyone can see the patch contents in-line in the mail, and
   * you can add a "cover letter" -- a message to the mailing list about the patch.
\ No newline at end of file