How do I Disable Macros on a File where Macros were Previously Enabled?

This is probably an easy question, but any of my searches have returned nonsense - perhaps I'm not searching for the right key-words.

I have a Word document (Office 2010) that contains an Auto-Open macro. I enabled the macros to allow me to use them, but now I need to see what happens when macros are disabled and the document is opened.

When I change the settings in Trust Center to disable macros and restart Word and then open the document, the macros automatically run because Word has remembered that macros were enabled for this document before.

How do I change it so that I get the macros disabled again? How do I 'clear' the memory of this document? Is there a way?

Any help will be greatly appreciated.

Many thanks,

Andre

Unfortunately I can't do that, because I want to show what happens when macros are disabled for that document (without me saving it as something else - I'm trying to validate it and so I can't change anything).

Thanks anyway.