Cover-up labels specially designed for the re-labeling of already frozen vials and tubes that cannot be thawed. These opaque, blockout labels stick to frozen containers freshly removed from liquid nitrogen or -80°C freezers, even in the presence of frost and moisture, and completely obscure the existing labels and obsolete information. They are ideal for the re-labeling of frozen cryo vials and tubes at -80°C when removal of the existing label is not possible. The re-labeled vials can be stored back inside liquid nitrogen or ultra-low temperature freezers for further preservation, even for decades. Once applied with clear overlap, these labels are waterproof and are able to withstand multiple freeze-thaw cycles. They can also be used for dry-ice storage and transportation.