How do I tell the difference between used and unused TEREA sticks?

Used TEREA tobacco sticks have two indicators that tell you if they’ve been used. The paper around the filter is slightly creased, and there will be a slight tobacco vapor stain on the paper. We recommend you dispose of the stick immediately after use to avoid any confusion. Another way to avoid reusing a TEREA stick is by placing it back in the pack upside-down. When you select your TEREA stick check that the wavy line is visible.