0JumpStart 10 years ago Sand and clay. At a craft shop, you'll be able to find some clay that must be fired to keep its shape. Do not use self hardening clay. You can experiment with adding water to the sand/clay mix or just mixing the two ingredients without to see which works best. The reuseable clay/sand mix will dry, holding the sand in place. Soak your whole construction to dissolve the mortar when you want to reclaim the bricks.