Some time ago Doug Hillary explained to me how the oil blotter test works and I have found it intriging. Per his advise I found this so I thought I would pass this along for those interested. Yesterday I tested the Focus with 5400 miles and it teated nearly clear. Here's the link.
http://www.acustrip.com/specs/onedrop.html
http://www.acustrip.com/specs/onedrop.html