Consider the following scenario. A person left his home in Eretz Yisrael to go to Chutz L'Aretz for Pesach. He remembered before the zman issur in Chutz L'Aretz that there was a piece of challah (from being mafrish challah) that they forgot to get rid of. They are unable to get to the challa and unable to get a shliach to burn or throw it away now.
May the person "sell" this to a gentile? Is there any problem of selling challah to a gentile? Perhaps since it either must go to a Cohen or be burnt that one shouldn't give it over to a gentile. (please provide sources.)
I realize in this particular scenario there would perhaps be other solutions (I decided not to focus on them in this question in order not to have to much written here in the question that is not directly related.) I made this up in order to ask specifically the question of selling it to a gentile. Perhaps when more answers come about I'll re-post the question and give the opportunity for others to post answers with possible solutions for this situation.)