Name the common elements present in anode mud in the electro-refining of copper

Anode mud contains metals like Ag, Au, Pt etc. which are less reactive than Cu. Actually, they are not in a position
to lose electrons though they constitute the electrode which acts as anode. All these metals are left as residue under anode (known as anode mud) while the entire copper present participates in the oxidation half reaction.
Cu(s) → Cu2+(aq) + 2e–