This past summer I moved a tank with a 4 (?) year old sandbed (4-5" deep) to another room. I removed a large rock that was resting on the bottom of the tank out of the sandbed. I then proceeded to replace all the rockwork and fill the tank.
Every zooanthid, poly, mushroom, starfish, crab, etc. literally melted.
Keep a cupfull to add to your new sand but I'd chunk the rest.
