You could engrave something on it then sell it to someone. THne you could use the money you got from selling the brick and donate it to the charity. That money could then go on to help someone become well, or save someones life. If it saves someones life then there is a chance they would spend money on something, then this money would enter someone elses possession and once again they will spend it. So by now, 300 people have spent this money, then the 301st person might donate it to the MY.
In effect, you donated an engraved brick to MY.