In the US it should soak off. Soak the stamp in water and be patient. After a few minutes, the gum is supposed to dissolve allowing it to be removed. Don't rush, or you will ruin the stamp.
Yes most carpet tiles available on the market are self adhesive or as the manufacturer's say "self-stick" tiles. They come in a great variety of colors and styles.
Self-address mailing labels refer to pre-printed labels that people use to save time, improve mailing accuracy, and add some personality to their mailings. They are available in rolls or sheets. You...