Regular glass jars break easily at freezer temperatures. Choose wide mouth, dual-purpose jars made for freezing and canning if you wish to use glass. These jars have been tempered to withstand extreme temperatures and the wide opening allows easy removal of partially thawed food. Covers on rigid containers should fit tightly, if they do not, reinforce the seal with freezer tape. Freezer tape is especially designed to stick at freezing temperatures. http://www.mtehomelife.com/refrigerator-storage/organizing-freezer-drawer/