Simple mixin to integrate a box-shadow and include a filter-expression for oldIE. If the box-shadow is inset the filter will be omitted as it doesn't provide inset-view.

box-shadow.scss

@mixin box-s($x, $y, $offset, $color, $inset: false) {
    $ie-color: ie-hex-str($color);

  @if $inset {
	    -webkit-box-shadow: inset $x $y $offset $color;
			    box-shadow: inset $x $y $offset $color;			
	} @else {
	    -webkit-box-shadow: $x $y $offset $color;
			    box-shadow: $x $y $offset $color;	
		filter: progid:DXImageTransform.Microsoft.dropshadow(OffX=#{$x}, OffY=#{$y}, Color='#{$ie-color}');				
	}
}