Like a solvent. Sweet ether, starting fluid, carb cleaner, or strong solvent based glue.
Greasy fluid is also how leaking electrolyte is described.
Sound like you probably do have a leak. I'm sure we'd all like to see some pics if you feel like sharing, but you don't have to.
Leaking without bloating implies some kind of mechanical failure. Case damage, terminal torque, terminal stress, or faulty seal from the factory.