What exactly do you mean by "a new lubricated shell"?
>On the contrary, back in the last century, i came across number of squealing
>cassettes, mostly of the low cost variety, that would show the same >symptoms
>even when new. They were obviously cheaply made, and usually the only solution
>was to move the tape to a new lubricated shell.
>I don't deal with a huge number of cassettes, but own many old ones and have
>never seen a sticky-shed cassette, not that you haven't!