Selecting the correct Blast Media

We are looking for blast media to support a small R&D function. The objective is to obtain a surface cleaning only. The items that will be subjected to the blast cleaning process include Aluminum & Steel. It is important that the media is fine enough to leave little to no distortion and not cause a health risk to the operator. Use will be between 5-10 small parts (10"X15"X5") per month. All blasting will be done with a hand-held tiggered gun. What is a good media type and size for the aforementioned needs.

Thanks,

It would help to know if your parts get plated or coated; however, one of the safest blast media for cleaning use are organic materials. Another common media that get good results are glass beads. Actually almost all blast media materials are safe if used and handled properly; therefore, I go back to my first statement.