Start as early as you can to teach your kids the value of donating. After you have completed an organizing session or have cleaned their room, take them with you to the donation center. They will be able to see the whole process and trust that items are going to someone in need, rather than just feeling like you wanted to have them clean their room.
** I don’t recommend ‘ambush’ organizing your children’s space. Meaning to go through with a garbage sack and taking out what you don’t think they need. This may actually cause them to hoard more and have issues with getting organized. Make sure they are involved in the process.