Hi,

I like to use a disposable BBQ when camping, but just putting it down on the
grass causes the grass to get burnt, and it's not always easy to find a
suitable rock, so I'd like to pack some kind of flat tray to put it on. So
far I have rejected the following materials:

wood: (will burn)
metal: (conducts the heat)
paving slab (too heavy)
asbestos (difficult to source ;-)

surely someone else must have thought of this

TIA

Andy