Gold stripping with electrofier

We have been melting 24k gold into cavities in platinum rings
and then stripping the top layer of gold with a solution of 17%
sulfuric acid, 17% muratic acid, and 66% water in a rectifier.
We put the anode onto the ring and leave the ring in the solution
for about 30 seconds. We repeat this process two or three times.
I would like to know if there are other methods or solutions I
can use to get the gold to look less yellow, darker and make the
surface look more like cork.