My very thoughtful Polish, English students have been asking me (very nice present continuous!) what I think about England's performance.
I could write a book on the subject but I will spare you the details, basically, you just can't make a silk purse out of a sow's ear.
This idiom means you can't produce something high quality with poor quality materials. A sow, if you are wondering, is a female pig.
To find out if it's true, watch this video about make overs - you know, when women go to a beautician or Trinny and Suzannah for a new look.