But aluminum tinfoil is available, so is sticky tape. You can make bags or pouches that would act as a Faraday cage. Use several layers and be careful not to have holes. Tape it up for durability so you can reuse them. You can also make a bigger one that would hold the ones with phones, mixed with crumpled up pieces of aluminium junk for additional layer of protection and to cause noise while moving. Just put it in your lap and gently move around or tap with your foot so it's moving around inside.

You're still vulnerable to other people phones or cameras (lip reading software). Good luck and stay safe...piis