Clean Viruses work / don't work if compressed

[Rishi Gangoly]

Hi,

I noticed that if a word document is infected with a Macro Virus and is
attached in an email, it gets cleaned and sent to the recepient.

However, if it is compressed, it does not. It just puts it in the quarintine
folder.

Is there a way to clean a file even if it is compressed?

Is this a something the AntiVirus software has to be capable of, OR
mailscanner?

Regards

Rishi