Gather conductive material such as aluminum foil, conductive fabric, or a metalized anti-static bag
Gather an insulating inner layer such as cardboard, cloth, or bubble wrap
Choose a non-conductive outer layer such as fabric or plastic
Wrap the inner insulating layer around the item you want to shield
Enclose the insulated item completely with the conductive material
Make sure the conductive layer has no gaps, holes, or exposed openings
Fold and overlap all seams tightly so the conductive layer remains continuous
Add a second conductive layer if needed for better shielding
Place the wrapped item inside a sealed non-conductive outer pouch or bag
Test the bag by placing a phone inside and checking whether it loses signal
Repair any weak spots, tears, or openings if the signal still gets through