Jill, I have been freezing cake mixes for years. I buy many cake mixes when on sale and put them in the freezer and keep them up to six or eight months before use. Let stand at room temperature for about an hour, or place in your microwave at 30% power for 1 minute. I have never had a bad experice from doing so. I also freeze flour and browie mixes with good results, just be sure to wrap the flour in a couple layers of plastic wrap before placing in the freezer.