Media blasting with glass beads, or walnut shells, or plasic beads will all leave some residue of the media. This is primarily due to static electricity created by the movement of the media. We have used all three over the last 35 years; and found that a bath in hot soapy water followed by a bath in hot water, followed by a bath in cold water will break the static bond.
We have blasted hundreds of thousands of carburetor parts, as well as aluminum intakes, heads, pistons, etc., etc., etc. with zero problems AFTER we started the post-blast baths.
Media blasting is like any tool; used properly, it will save you time. Improperly, and you get to redo everything, sometimes at great expense.
And I would agree with Grigg that suggesting the use of glass beads is not necessarily a good idea, even though we do use them. Simply purchasing a tool does not necessarily mean one has the experience to use the tool (no offense meant to anyone).
One caviat about using caustic lye on aluminum: some compounds of aluminum will GIVE OFF TOXIC!!!!! FUMES WHEN SUBMERGED IN CAUSTIC LYE! Be very careful if you chose this method.
Jon
