How to "unload" a xml?

[SIZE=3][FONT=Times New Roman]Hi…[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]I am using this code to load text from a xml file[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman] [/FONT][/SIZE]

[SIZE=3][FONT=Times New Roman]XML.prototype.ignoreWhite = true;[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]var audiolist_xml = new XML();[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]audiolist_xml.load("total.xml");[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]audiolist_xml.onLoad = function(success) {[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]            if (success) {[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        eachTrack = this.firstChild.childNodes;[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        _global.totalTracks_streets = eachTrack.length;[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        trace("inside");[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        m_total_songs = totalTracks;[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        trace(_global.totalTracks_streets);[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        var i = 0;[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]                        [/FONT][/SIZE][SIZE=3][FONT=Times New Roman]  ….[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]            }[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]};[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman] 

[SIZE=3][FONT=Times New Roman] [/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]So it is loaded… The question is: how to UNLOAD it when I don’t need it anymore and by doing this, free some memory that I need to use…[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman] [/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]Thanks a lot,[/FONT][/SIZE]
[SIZE=3][FONT=Times New Roman]Cheers.[/FONT][/SIZE]
[FONT=‘Times New Roman’]Leo.[/FONT]