I keep some of my overflow of fabrics & scraps in my garage and also check thru them from time to time and i haven't had any problem.....I live in Oregon so it's different weather then some but it gets very hot and cold in my garage also.
they are all stored in tote boxes except for one bunch i have in a laundry basket with a large towel covering the top.....one lady donated fabrics to me and they were very smelly being kept in cardboard boxes in her garage i think.
i used the vinegar solution in my machine to get rid of the odors....polyester knits I gave to Goodwill.....