Answer: They exchange precious metals for small amounts, but mostly use the produce that Funaho brought from Earth.
The True Tenchi Novels bring up Funaho's gift basket multiple times.
It seems very random at first why this subject comes up multiple times in the novels,
But it's not random at all.
In GXP 2 it is revealed that Funaho has multiple private garden plants that grow plants cultivated from the seeds of the fruits that Funaho brought with her from Earth and that Kiriko buys the fruit from funaho and uses them to send Seina's family money.
By selling the fruits, which are superiorly grown in space age pesticide and defect free conditions, They can quickly exchange their currency on earth.
Precious metals have to be exchanged carefully because a large outside influx would crash the market. Fruit however, is bought in bulk and naturally goes bad after a few weeks on earth.
Kajishima thinks of everything.
The True Tenchi Novels bring up Funaho's gift basket multiple times.
It seems very random at first why this subject comes up multiple times in the novels,
But it's not random at all.
In GXP 2 it is revealed that Funaho has multiple private garden plants that grow plants cultivated from the seeds of the fruits that Funaho brought with her from Earth and that Kiriko buys the fruit from funaho and uses them to send Seina's family money.
By selling the fruits, which are superiorly grown in space age pesticide and defect free conditions, They can quickly exchange their currency on earth.
Precious metals have to be exchanged carefully because a large outside influx would crash the market. Fruit however, is bought in bulk and naturally goes bad after a few weeks on earth.
Kajishima thinks of everything.