Yeah fetish hoarding and the worries for money are (almost) gone in mid-lategame .
Earthincome i rarely convert into gold because there are so many imo "better" uses for the earthgems like further hammers , casting the forge of ancients or hordes of mechanical men etc. etc. .
Very often you are lucky enough to find a province with jade sorceresses . Some of them will have a random fire then and can be used for fetish forging . Most can be used for clamforging as well
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The only 2 summons which can get NF are afaik tartarians and spectres .
If you can cast the forge for a few turns though every of your mages can build fetishes quite cheap and you will quickly swim in them .