Believe it or not it's true! There's a better solution. 

I'd like to HIGHLY recommend a new 'toy' I bought for cleaning vintage sewing machine parts. It's a 'Costway 2.5 L Digital Heated Ultrasonic Cleaner' with a heat option. I ran these parts through several times, with the heat option on, and they look like new! I added a dime sized amount of simple green to the cleaning chamber.

I didn't scrub the parts at all, I simply wiped them off and they look new! It's the last time I scrub any old grimy part! I looked at so many ultrasonic cleaners before I settled on this one, because it has the perfect size basket area to lay the face plates down in. I chose this model with a heat option to help lift the nasty grime. It's simply awesome.

The price was decent too, considering there are other more expensive options out there. The pictures tell no lies.

Buy a  Heated Ultrasonic Cleaner 

I added a dime size amount of Simple Green to the tank.

The parts before cleaning.

You can see the grime lifting off of the parts

The ultrasonic cleaner running with the heat option on. I ran it through the cycle a couple of times

The parts after cleaning and I didn't scrub them!

Buy a Heated Ultrasonic Cleaner