Indian feudatory state Kota used canceler implements as postage stamps.
Kota 1883–4 2Paisa Riyasat Kota black on yellow imperf. stamp (Staal 5)
Gibbons is as usual stupid and useless as it still refuses cataloging Kota stamps which saw genuine postal usage.
References:
1. Kotah Stamps and Postal History.
Johan Frederik Staal.
Gibbons Stamp Monthly (Vol.XXIII No.6 11/1992); p.65
2. Some Notes on the Postal History of the States of Kotah and Jhalawar.
Peter Röver.
India Post (Vol.XLVI No.2 Issue 185 4#8210;6/2012); pp.110-1, 114
3. Postage Stamps of Kotah State.
Phiroz M Medhora.
The Collectors' Club Philatelist (Vol.LIII No.6 11/1974); pp.349-53
4. Stamps and Postal History of Kotah.
Phiroz M Medhora.
India Post (Vol.VIII No.3 Issue 41 6#8210; 9/1974); pp.55-60
5. Dungarpur#8210;Kotah#8210;Shahpura.
Peter Röver.
The London Philatelist (Vol.XCV No.1119-20 3#8210;4/1986); pp.47-56
6. Dungarpur#8210;Kotah#8210;Shahpura An Emendation.
Peter Röver.
The London Philatelist (Vol.XCV No.1123-24 7#8210;8/1986)
7. Kotah Stamps and Postal History.
Johan Frederik Staal.
The London Philatelist (Vol.CXIV No.1326 6/2005)