Find an organization or company that accepts old windows and doors by using the directory put together by the Building Materials Reuse Association (see Resources). This directory is divided by state and lists green building companies and salvage yards that will buy your glass or accept donations.
Contact local nonprofits that use building supplies, such as Habitat for Humanity. You can also contact local theater companies or art collectives. Offer to donate the windows and doors to them, then take a tax write-off at the end of the year. Your old windows can become a base for paintings, a set for a play or the windows of someone's new home.
Contact salvage yards near you and ask if they accept old glass windows and doors. If they do, ask for the price and arrange to drop off your materials.
Take your glass to any of the companies or organizations listed on the Materials Exchange (see Resources). The Materials Exchange lists both for-profit and nonprofit companies that need products like old glass doors, and it's sponsored by the Northeast Recycling Council.