SSI exemption scheme for clearances grants concessional duty treatment and nil rate inputs subject to a written option and aggregation rules. SSI exemption permits specified small scale clearances for home consumption to be exempted to the extent duties exceed a concessional rate, subject to two operative categories: initial clearances up to an aggregate value at a concessional percentage of normal duty, and clearances used as inputs for further manufacture within the factory which are nil rated. Eligibility requires a written option before first clearance, notification to authorities with prescribed particulars, aggregation across factories and manufacturers, and compliance with exclusions and valuation definitions.