I am cleaning some of the suspension bits and I am having a hard time removing the waxy factory undercoating. What is the best method for removing this.

 

Fine wire wheel.

I did it on my oil pan-

 

It's called cosmoline. Red Brake Cleaner should do it.

 

yep, cosmoline. Some have used kerosene to remove it. I use lots of stiff brushes and simple green and soap. Note - Simple Green is very corrosive on Aluminum, so while it is effective, it must be washed off immediately with soap water. There is no quick way to remove the cosmoline. It's an intensive labor job, and for the underside of our cars, not really worth it IMHO.