Thanks very much for all your comments - this is what the Forum is good at: helpful info and a ready-made consumer study group!!

I shall ditch that idea - but just to put the record straight, in case anyone was thinking I meant to put pots of creams and things like that which people had put their grubby fingers into already - I certainly didn't, and only intended things like hair products maybe used once or twice.

Back to the drawing board!