I would not open suspicious items on your main computer. You might have noticed that your AV and all OS patches come AFTER the event?

Get an old machine to do this sort of thing on. If your main machine's AV lets you download or open malware then it is not protecting you against that malware?

Convert the file into a .txt file and open it in a program editing utility such as notepad or vi

Do not use Word, or similar high level text editors, as they can launch executables.

Just because an attachment passes you scan does not mean that it is safe..............or there wouldn't be any viruses?

Do be careful