Ban .html as attachment but not html mails?

[Remco Barendse]

MOre and more malicious emails are coming in with .html as an attachment.

I do not need my users to receive .html files, ever

Blocking them in /etc/MailScanner/filename.rules.conf
#deny   \.htm$          Dangerous attachment type 
#deny   \.html$         Dangerous attachment type

Blocks every email in html, not exactly what I wanted.

What is the proper way to do it?

Thanks!!