Cashews still in their shells are spread on mats to dry in the sun. The outer shells are leathery, very tough, and filled with a toxic acid which causes pain and blistering of contacted skin. The effects are even worse when people try to crack the nut by biting! Nina collected a few on the ground, separated the nuts from the fruit, and put the nuts in the sun to dry. She developed areas of skin rash similar to poison ivy and was very uncomfortable for several days.