separateBrushes.jsx

//snippet to separate brushes into different layers
//CC-BY, Nik Ska, 2014

var separateBrushes = this;

separateBrushes.separate = function(_removeOrigin){
    var activeComp = app.project.activeItem;
    if(activeComp && activeComp instanceof CompItem){
        var sel = activeComp.selectedLayers;
        if(sel){
            //getting first selected layer brushes
            var brushes = sel[0].property("ADBE Effect Parade").property("ADBE Paint").property("ADBE Paint Group");
            if(brushes){
                app.beginUndoGroup("Separating brushes");
                for(var i = 1; i <= brushes.numProperties; i++){
                    //first we duplicate a layer
                    var newLayer = sel[0].duplicate();
                    newLayer.name+= (' - ' + brushes.property(i).name);

                    //now getting its brushes
                    var newLayerBrushes = newLayer.property("ADBE Effect Parade").property("ADBE Paint").property("ADBE Paint Group");

                    //cycling though brushes and removing the ones we don't need
                    for(var j = brushes.numProperties; j>0; j--){
                        if(j!=i) newLayerBrushes.property(j).remove()
                    }
                }
                //disabling original layer
                sel[0].enabled = false;

                //or removing it
                if(_removeOrigin) sel[0].remove();
                app.endUndoGroup();
            }
        }
    }
}

separateBrushes.separate(false)