A British white label test pressing of Incesticide was apparently sold by eil.com, as one was previously marked as "out of stock" on their website [1]. There is no version of the album manufactured in the UK, and while it could have been a test pressing for a cancelled UK pressing, it was most likely the 1992 Dutch edition, or the 1997 French edition, GEF 24504 in both cases.
The book Heavier Than Heaven by Charles R. Cross mentions a Smells Like Teen Spirit 7" test pressing which the band's radio promotion representative brought to the radio station when they visited KXLU studios in Los Angeles on August 15th, 1991 [2]. The single was released on September 10th, and it is plausible that they would have test pressings ready at this time. The only American 7" is DGCS7-19050, a few matrix variations were released but ultimatley the stampers were all sourced from the same lacquers. The B-side is Even In His Youth.
A British 7" test pressing was on an Italian dealer's sale list in the late 1990's [3]. Two matrix versions were released, both with Drain You as the B-side.
See Unconfirmed Pennyroyal Tea items for all rumored test pressings.
According to Frank Cotterell, owner of Waterfront, these test pressings are long gone. He never sold them, so they were most likely lost or recycled. [4]