1/ With those Brass compresion fitting nuts on Copper pipe.
I put the pipe flat on concrete & bash the nut with a hammer, maybe twice, then I rotate the Copper pipe 90 deg & bash the Brass nut again, normally it cracks & falls off.
Brass is made from Copper & Zinc, so theres no problem with leaving Copper on the Brass stuff.
2/ I think I weighed up the Brass pins on a plug & got 8 grams Brass ........
3/ Gold, Gold was $1800, now its not. Theres nothing thats solid Gold in a computer.
Its all Gold plating & you actually remove the other metals from Gold bearing scrap, rather than removing the Gold from the Gold bearing scrap............ Thats why it takes so long & involves lots of really dangerous stuff & chemicals.
Best way to get Gold is to sell your Gold bearing stuff for a good price, then buy some 99.999% Gold with it.