What should I do with my collections of stamps and coins after learning that collecting them is impermissible (haram), and is it permissible to sell them and donate their proceeds to charity?

We previously discussed stamp and coin collecting, and it is not haram. However, it is a waste of time and money on something that has no benefit, so this hobby should be abandoned. If he wishes to sell them and donate their value, that would be better, but it is not obligatory for him.