Dear all,
 Can anybody tell me what is the exact method to get  an spotless surface of
polycrystalline electronic grade copper from  electrochemical polishing. The
copper surface initially has an average roughness of 150nm.
 I am using ortho-phosphoric acid 85%  aqueous solution, but ultimtely leaves
few spots looks like watermark  (although I tried to clean that with water and
acetone).
  For rapid polishing, I am trying with 6 V and current density of 3-4 amps/cm2.
  I am using same copper for the counter electrode.
  Please, suggest me a rinsing method if possible to get rid of the marks.
  I appreciate cooperation.
  thanks,
  Biplab