Are those wire looking things actually wires? If so, they might be magnetic. If they are it might be easier to get a big magnet and just hover it over a small ammount of the sand and get them out that way.
If they are something other than metal or not magnetic you might get away with using a strainer or something, but I don't have any experience with this material and don't know if a properly sized strainer is available.
Just my two cents.