IMO the best way to make gold is by running the mausoleum.With 80% gold loot,i can make around 20k pure gold from maus 1-4.You can also sell the pink you get plus balance token which you can use to buy coffer or balance bar.
The only bad news is you need to run 30 minutes to 1 hour non stop.

Sent from my HM NOTE 1LTEW using Tapatalk