it also explains the mystery "INPUT SIGNAL" pin on the old 4-pin IBM Thinkpad power connector. this pin simply increases the output current limit when it is pulled low by the laptop. it's because the power brick is also the battery charger, and when the laptop is turned on, you have to increase the current to compensate.
anyway, isopropyl alcohol wipes and a bath in Simple Green has mostly taken care of the bad smell.