I have put a box of cookies in the neighbors car. I'll pull them out tomorrow and then let you know what happened.
I’m sorry I forgot to say what happened. I put the cookies in a neighbors car for 24 hours during the middle of a hot summer day. The car is kept outside. Some cookies were in a heat sealed bag and the rest were in the box without bags. All looked fine, but the chocolate ones cookies in the bag fell apart when handled, but tasted okay. The vanilla ones were very soft, but held together. The cookies without a bag looked fine but were very hard. The vanilla cookies were so hard that they were difficult to break.