In the last few months, I've been receiving a heap of spam from China. Luckily, I've found a way to identify mail in Mail.app with that character set so that it can be marked as junk. To do this:
- Select Mail -> Preferences -> Rules
- Select Junk -> Edit
- Select (+) to add a new rule.
- Click on the "From" drop-down and select "Edit Header List..."
- Add "Content-Class" by typing "Content-Class" in the "Header:" text box and then hit "Add Header" and "OK."
- Set the first pop-up on your new rule to Content-Class, the second to Contains, and the third to charset="gb2312".
- Select (+) to add a new rule.
- Set the pop-ups to Subject, Contains, and charset="gb2312".
- Select (+) to add a new rule.
- Set the pop-ups to From, Contains, and charset="gb2312".
- Click the "OK" button to end the rule definition.
I'm happy to say that this gets 100% of the Far East spam that I was receiving!