adobe illustrator - Automatically make various multiple stroke colour the same as various underlying fill colours.

I have auto traced a photograph in illustrator - its got thousands of vectors once I expand it and illustrator has converted each of them to a filled colour - I want to now trace the edges of them with a grungy brush but using the underlying fill colour. Where in illustrator can I stroke or outline these fills using the underlying colour - surely this is something that the program automatically does?

I've found this script online but don't know how to implement it. I'm new to this so any help appreciated. Many thanks.

James

var idoc = app.activeDocument;  
var sel = idoc.selection;  


for (i=0; i    var ipath = sel[i];  
    ipath.stroked = true;  
    ipath.strokeColor = ipath.fillColor;  
}