On Earth Day, April 22, Russo Music Academy, 619 Lake Ave., Asbury Park, is holding a guitar string recycling program from 5 to 8 p.m.   In conjunction with D'Addario, which is rolling out what they say is the world's first wide-scale recycling program, Playback, Russo is offering a free set of strings and restring on any qualifying 6-string electric or acoustic guitar when you bring in used strings to contribute.   Customers can choose between a set of D'Addario's premium NYXL electric guitar strings or D'Addario's NEW Nickel Bronze acoustic guitar strings.   The free strings are limited to one per customer, and restrictions apply.   Playback is powered by TerraCycle, an international upcycling and recycling company that works to collect difficult-to-recycle items and repurpose them into innovative products.   Visit russomusic.com for more on Russo Music Academy.