You have to do it every day, one a day, but it adds up to a lot.

Auction houses generally sell "broken necklaces", ranging from150 to 200g. With this, you can get the task and exchange it for a jewelry coin. As long as you have the goods, you can buy them indefinitely.

It's not cost-effective to blow up the titan mine.

Also, do you need to learn all the drawings (of course, learning is for the goal)? There are only a few commonly used in the market. You can save some coins first and then change them into drawings when someone needs them.