The materials used in many laminators often contain chemicals which can adversely affect the print on thermal labels. These chemicals can cause the print to fade or turn the label black. Labels should not come into contact with materials composed of PVC film and vinyl containing plasticizers.

The following information ONLY applies to DYMO label printers that use direct thermal printing technology. Currently, this includes all LabelWriter™ printers, LabelManager™, LetraTag and Rhino series label makers. When stored properly, DYMO labels will have a shelf life of several years. When used in an office environment, printed labels will remain legible for over a year. The following conditions may cause labels to darken or the text to fade: exposure to direct sunlight or fluorescent light for an extended period of time, exposure to high temperatures for an extended period of time, contact with PVC film or vinyl containing plasticizers.

DYMO's One-Day Self-Expiring Security Stickers come in two parts. The "front part" labels are marked with the letter 'V'. The "back part" labels are marked with a grid of crossing lines. To use a Security Sticker (and start the one-day expiration process), peel off a "front part" label and place it on top of a "back part" label. After 24 hours, the grid from the "back part" label will bleed completely through and become highly visible, obscuring the letter 'V' on the "front part" label.