We have a tzedakah box in our house which was leftover from renters before us.
I just read the label on it and realized that the money goes to the kollel of a certain Rav who became known as a Rasha. What do we do with the money?
The money should go to the place that it was donated. Whatever the rumors are, (which are surely lashon hora and most probably motzei shem ra), it has nothing to do with the people of that kollel that need the support. Aside from this, being that the people already donated it to them, it has to be given to them.