THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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However, none of this is just as quick and simple as setting up a quick procmail rule and having your users just forward messages.
Maybe see: http://jousset.org/pub/sa-postfix.en.html. This has details on how to setup an account that users can simply forward spam/ham to. (It uses a perl script as the transport which strips out header stuff....)