The gasket between the two metal halves of the case on old Conner laptop drives sometimes turns to goo, leaving a big mess in the laptop and a (relatively speaking) big gap between the case halves. I haven't taken one apart to see if the goo ends up on the platters as well.
We're talking ca. 1991 drives here, with 60 MB of capacity and IDE interface. CP2064. They were used in Outbound laptops, or, at least, they're compatible with Outbound Laptops. Good replacements for the old PrairieTek drives if the gasket hasn't turned to goo.