Corrosion on one tin containing shrimp, say (10)
I believe the answer is:
crustacean
'shrimp say' is the definition.
(shrimp is a kind of crustacean)
'corrosion on one tin containing' is the wordplay.
'corrosion' becomes 'rust' (rust is a kind of corrosion).
'on' is a charade indicator (letters next to each other).
'one' becomes 'ace' (ace has a value of one in some card games).
'tin' becomes 'can' (synonyms).
'containing' means one lot of letters goes inside another.
'rust'+'ace'='rustace'
'rustace' inserted within 'can' is 'CRUSTACEAN'.
(Other definitions for crustacean that I've seen before include "Such as a barnacle" , "Woodlouse, say" , "crab maybe" , "life form with hard case" , "Such as a crab or shrimp" .)