Salt in cigarettes (3)

I believe the answer is:

tar

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'salt' is the definition.
(both can informally mean a sailor)

I cannot understand how the rest of the clue works.

(Other definitions for tar that I've seen before include "Informal sailor or coal distillation" , "Sticky substance used in road construction" , "Sailor; bitumen" , "Road-making substance" , "Informal sailor, the rat" .)

I've seen this clue in the Evening Standard and The Globe and Mail.

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