| (a) | - | the stamp on any paper inadvertently and undesignedly spoiled, obliterated or by error in writing or any other means rendered unfit for the purpose intended before any instrument written thereon is executed by any person; |
| (b) | - | the stamp on any document which is written out wholly or in part, but which is not signed or executed by any party thereto; |
| (c) | - | in the case of bills of exchange payable otherwise than on demand or promissory notes- |