Parcel insulation material (Preston Park area BN1)

We have 16 sheets of parcel insulation material (came with HelloFresh food delivery boxes) to give away. I used what I could to fill up cushions and make a dog bed but don't have any more use for them. They are all slightly different sizes but approx. 35cmx100cm. I don't know what they're made off so propably not fire safe if that's a concern.