In the early days of the United States post office, postmasters were responsible for defacing stamps to prevent reuse. Clerks might draw across the stamp with a pen or otherwise mark the postage. It became the practice to use cork bottle stoppers, carved with various notches and then dipped in ink. The process left room for creativity and designs became unique to the clerk who carved them. Motifs included simple Xs and geometric forms, stars, hatches, animals and more. The practice lasted from 1847 through the 1890s. Outside of the US, these decorative marks are called cork cancellations.