SUDAN. Siege of Khartoum. 1000 Piastres, 25.4.1884. P-S107b. PCGS Choice About New 55 Apparent. Rust Stains.,A nice 1000 Piastres example from the Siege of Khartoum. PCGS mentions Rust Stains in the comments section of their holder.,PCGS Choice About New 55 Apparent. Rust Stains.