Q:    "How do you recommend pre-cleaning the parts to get them ready for vapor blasting?"
A:     Pre-cleaning is critical to achieving perfect results.  Place your dirty parts in four gallons of kerosene and let them soak for a week or more. This will dissolve 99% of all your grease and oil.  After that, any sand or asphalt left over should be soft enough to blast away.
Q:    Do you clean anything else
besides classic British, American,  
or European aluminum parts?  
A:    Carburetors vaporblasted, disassembled and ultrasonic cleaned. Small block intake manifolds, bronze cylinder heads. Your diecast engine will have blemishes from the factory that may or may not come out by vapor-blasting.

  Q:  Is vapor blasting really that much better than other blasting methods?
  A:  Yes, and you can see the difference yourself--from thirty feet away!
  The crank case half on the left was vapor blasted cleaner than the day it came out of the crate.
  And you can see how the right side was actually damaged  by dry bead blasting.  You see  the factory texture is almost all sanded away and the corners rounded over.  The outside is dull and grey and full of  micro-scopic pits that will absorb oil and gas the first time the engine is started.  You can see microscopic "sparkles" in the aluminum.  Those are particles of fractured glass that are stuck in the surface pores.