Do you really need to kill your strategy?
Maybe not. If you are a strategy manager on Collective2 -- that is, if you have started your own strategy -- your credit card will never be automatically charged for your strategy listing fee. We do not automatically renew your strategy at the end of its six month term. You need to explicitly ask us to do so.
Therefore, there's no need to take action in order to prevent billing. However, you may still choose to explicitly "kill" your strategy. This prevents potential investors from subscribing to your strategy. Also, by killing the strategy, you make it harder, but not impossible, to find (it won't automatically appear in The Grid or in automatically-generated lists of strategies). Keep in mind, though, that the trading record remains in our archives, available for people that explicitly search for it. This inability for strategy managers to practice "selective hindsight" is part of C2's philosophy about honesty and transparency -- and it maintains the integrity of the site, to the benefit of investors and strategy managers alike.
How to kill your strategy
Keep in mind that if you kill your strategy, you CANNOT change your mind and bring it back to life. Also, if you paid a listing fee for the strategy you are about to kill, you cannot apply it to another strategy, regardless of how much time your system was alive.
To kill a strategy, log in to C2 and go to your strategy's detail page. Click the Manage button, then click Kill Strategy.