How to get angry grandmas in cookie clicker

Selling a building (grandmas are considered to be buildings) earns you 50% of the cost of buying another of that building. This is about 55% of what you paid for it.

You need to have Cookie Clicker as your active tab to let Raptr track your gametime and the browser doesn't need to have focus. If you're browsing with multiple tabs, everytime you switch out from Cookie Clicker, Raptr will notify you something like 'Cookie Clicker - 9 seconds played'.

This behavior has been tested with Chrome and Firefox. With Explorer I'm under the impression that gametime isn't tracked at all.