[hcoles]

I found this posted online for a company in Tucson AZ that does vapor blasting.

How to you prevent blast media from becoming trapped in my parts?

With regard to blast media, the first order of business is to start with a clean part, including in the oil passages and galleries, which are very thoroughly cleaned. Oil and other engine passages are then plugged or masked. Any part with a thread is also plugged to prevent media from lodging in the threads. After vapor blasting parts are immediately rinsed, several times, and then dried with compressed air. Then the plugs and masking are removed and the process is repeated. It is however the customer's responsibility to verify that no blast media is present and the parts are ready to be put back into service.