Lightweight items such as organics(leaves, acorns, wood, etc), or plastics will tend to float up in your tank, which can be very frustrating when you are trying to keep them submerged in the electroforming solution. You can weigh them down simply with a piece of glass for an anchor and a short nylon string. Both of these items are non conductive, and resistant to the solution's acid, so it will not interfere with your electroforming.I offer an anchor set as a kit add on, if you do not have something suitable yourself.