My mum has asked me to melt down her 9ct white gold wedding ring and make her a more modern looking plain band . I know there are loads of issues with white gold, but it really has to be the same white gold. So questions:

1. The ring was bought in england in the late 70's - so what is the alloy likely to be?
2. I presume it will have been rhodium plated, although most of that is worn off - how do i get rid of the plating before I melt it down.
3. I know I have to use 50% new metal - could I use 18kt white gold to make the white gold close to 14kt? or should I stick with 9ct.

Cheers!
Lucy