Question: What should I do with Buddhist-related materials (such as old sutras, books and disks) that I no longer need?
Answer: The best thing to do is to pass them to friends who might be interested, or to bring them to Buddhist centres for re-circulation. Do ask for permission first.
For very old and damaged items beyond repair (including sutras), this is proposed: http://thedailyenlightenment.
Related Article:
How To Handle Wrong ‘Dharma’ Materials
http://thedailyenlightenment.