I've used contact cleaner. It's in a spray can, you can buy in the automotive section at walmart. Just point and shoot and all the goop is blasted away. Seriously the old gummy sticky oil just starts 'melting' off . I've only used it on the insides where it's gummy and yellow. So if you do go this way, test it first before really going gung ho. Then i just re oiled my machines. Metal on metal it works beautifully, metal on plastic you'd have to be careful because it does cool off the area being sprayed.