I am a Master Food Advisor with my county extension office. The only safe way is to use a pressure canner, otherwise you may get botulism. There are new varities of beans than there used to be and also stronger strains of bacteria. The only way they can be killed is at a temperature higher than you can achieve through just boiling temperature or 212 degrees. Process pints for 20 minutes, quarts for 25 minutes at 11 pounds pressure. Be sure to use canning salt, not regular or iodized salt. Use 1/2 tsp. per pint, 1 tsp. per quart.