The city is inviting residents to take part in a free book swap on March 15 from 10 a.m. to 1 p.m. at the Senior Center, 5 Broad St. Organized by SalemRecycles, the event is an opportunity for households to recycle their unwanted books, greeting cards, and commercial CDs, DVDs, and videos. All materials will be free for the taking. No actual swap is required; participants can donate materials, take them, or both. All books are accepted for donation, even textbooks. Anyone donating materials can drop them off on March 14 from 5:30 to 7 p.m., or from 9:45 a.m. to noon on the day of the swap. This marks the 11th time the city has held the book swap, which is intended to promote reuse of books and other media materials. SalemRecycles is the city’s all-volunteer recycling committee.