I had always only removed my throat plate and cleaned all the lint and stuff out of that area, bobbin area, etc. I wasn't aware I could get UNDER that area until I bought this book.
My hubby and I have since cleaned three other machines we own and got them running...only one needed a part to get it going and the part was only $4.95!
So most of them just needed a good going over with a toothbrush, Q-tip, and a piece of flannel!