How do I get the marks off

[mum_2_5]

Justin wore a pair of his shorties out into the paddock yesterday with daddy :shame: He fell over in the dirt and Now have big parks on the knees. What is the best way to clean them without the felting on me?

Shorties (http://i154.photobucket.com/albums/s248/mum_2_5/DSCF0331.jpg)