well, like a central bank (or a corporation buying stock on the open market to retire it into treasury stock), I think LL needs to be willing to buy L$ on the market and retire it.
I'm sure philip has many other things he'd like to do with his RL cash, but if the weakness of the exchange rate starts to threaten the content creation community, they'll need to take action.
I'm not saying the time has come, but it's a logical way to remove currency.