Once your brave is above roughly 60, the best way to use it (to make cash) is to conduct robberies. (YOU WILL NEED TO HAVE DONOR STATUS TO DO SO!!)

Go to the Explore page, and click on "User List". Then, click the "Money" link, and finally click "Descending".

This shows you a list of the currently richest players in the game, top to bottom. Generally speaking, players over level 80 or so will have a Theft Protection card, rendering them immune to robbery, but this is not always the case, for example, a friend has robbed players of Lv 200 and more. (Note that a higher level player is obviously a greater enemy to make)

Click on their name, and you will go to their profile page, where you can click the "Rob their home" link to attempt a robbery. Each attempt costs 15 brave irrespective of success, of which there is roughly a 33% chance. If the player is immune to robbery, yet they have a large amount of cash out, there is still a way to
steal from them.

If you feel they are weaker than you (and if they are offline, or have been inactive for some time (you have to be really ruthless, or the person particularly rich to mug them while they are online!)), you can attack and mug them to get some cash, guaranteed. Remember you must be in the same location as them, or use a projection scroll to attack them (only for the super-rich targets).

Notes:

Mugging is less effective than robbery, in terms of cash gained. You steal a much lower percentage of the targets total cash.

The targets cash must be sitting on them at the time of the robbery to be stolen.

When your brave is above 150, and the target has over 2.5 million sitting out, it becomes efficient to buy rice, and boost your brave artificially to continue stealing. Advice on this technique:

Open a second window, keeping the first on the persons profile page. This second window will be used to quickly buy rice, and boost your brave in the rice paddies (choose the "Sake" link). Then quickly click back to the first window and continue to rob.

For very quick robberies (using firefox), after clicking on rob their home, hit backspace, keeping your mouse near the part of the screen where the rob link is. Going back and forth quickly like this will very quickly drain someones money. Remember to look out for the events which send you to jail, and quickly use a few sneaky monkeys to solve the problem. If firefox isnt your default browser, youll have to edit it so that backspacing also refreshes the previous page. The reason for this is, you cannot simply refresh the robbery page, the previous screen must be refreshed instead.

Speed is of the essence in successful robberies. If someone is active while you are doing this they will quickly bank their cash, so be swift.

One last thing. Robberies dont make you any friends. Happy hunting!