How can I decrease the size of the outlook.pst file

How can I decrease the size of the outlook.pst file without compressing it? I want to open the file and delete some files in it and then close and continuing using it. Or can I delete one and make a new one without any apparent evidence?

Thank you

 

outlook.pst contains everything in Outlook, your email messages, contacts, calendar, etc. Are you willing to lose all that, which would happen if you delete outlook.pst?

 

By opening and removing some files. Or you can create a second pst file and use it. As far as i can tell/have seen its fine to do what your planning except if you delete one, you loose any stored messages or attachments in that file.