There is indeed something better, and it's designed for the purpose. It looks just like a toothbrush, except the brush bit is made of brass (or copper?) wires. I can't recall whether I picked it up from an electronics shop, a hardware store or a car repair place, but it's made for corrosion removal and cleaning. Dana's tips above probably are still good, but IMHO you're much less likely to leave bits in the machine with one of these.

Might have been the car repair place now that I think of it.

Of course, you realise with the washing comes the thorough drying before applying electricity, yeah?