Have no recollection of counterfeit tobacco's origin (6)
I believe the answer is:
Here is my best explanation:
'have no recollection of counterfeit tobacco's origin' is the definition.
I can't tell whether this defines the answer.
'counterfeit tobacco's origin' is the subsidiary indication.
'counterfeit' becomes 'forge' ('forge' can be a synonym of 'counterfeit').
'origin' says to take the initial letters.
The initial letter of 'tobaccos' is 't'.
(Other definitions for forget that I've seen before include "Be unable to recall", "Overlook", "Leave behind unintentionally", "Be unable to remember", "Don't remember", "Lose memory of", "Dismiss from the mind", "Stop thinking about", "Slip one's mind" and "Not remember".)