RBI has asked banks to strictly follow the Clean Note Policy and issue only clean currency notes to public. In a notification issued from Mumbai, RBI has asked banks to do away with stapling of note packets and instead secure note packets with paper bands. It has further asked banks to sort notes into re-issuables and non-issuables and withdraw soiled notes from circulation. Banks have also been asked to stop writing of any kind on watermark window of bank notes as it disfigures the watermark impression and recognition becomes difficult. According to RBI, an average of 20 percent notes is disposed off every year after getting soiled. The number of such soiled currency bills stood at over 13 billion units during the fiscal ended March 31, 2012. With a view to increase the shelf-life of notes, RBI will soon run a trial pilot project for plastic or polymer currency notes.