Sand on wax

I have a question on how to avoid getting sand on to the wax of my surfboard? I have a 7"4 funboard and I flip it over on the sand to prevent the wax melting but then sand gets on my wax and I see others do the same thing and nothing appears on theirs!!
. I was wondering how I should lay my board when I'm on the beach watching the sets and just hanging out?
