Old rooftop TV antennas can become shovel handles. Discarded bedframes can be feedstock. Owners of balky vacuum cleaners can learn how to maintain them, instead of trash them. Boomers with a house full of unwanted possessions can get advice on handing them off to new uses. Community Mercantile, a new nonprofit store stocked with re-used items that offers this kind of serious recycling to the town, has its grand opening this Sunday, Oct. 30. Today on Davisville, we talk with co-founders Larry Fisher and Stephanie Koop about what they’re doing, and why.