In some cases, revenues have been used provisionally as postage stamps. Mail flown in a rocket, even if only a short distance. Many rocket mail experiments have been conducted since 1931. Special labels, cachets or cancels usually note that mail was carried on a rocket. The design features a kangaroo on a map of Australia and was used as late as 1945.
Flat plates make single impressions.
No paper is actually removed from the sheet, as in perforating. Rouletting has been made by dash, sawtooth or wavy line. A brown mold, resembling the rust in iron. Rust affects stamp paper and gum in tropical regions. A self-addressed, stamped envelope.