Sorry Civil, it must be my Waterford ancestry kicking in
From what I remember, you mask off any areas that will not / should not be blasted with something like a heavy duty cloth based tape (normal masking tape is no good as the sand will just blast through it).
Make sure all holes are bunged (we always used rubber ones) as any media getting in is a pain to remove.
Always blast at the lowest possible pressure.
After blasting with sand, you can then get a really nice finish by then blasting with glass bead (you can leave the same masking on, just make sure it's still covering what should be covered).
Then remove the masking and all the sticky residue the masking leaves (tip: to help remove any sticky bits dab at it with a new bit of sticky tape)
When you've done all that, make sure all traces of media have gone from holes, crevaces, etc.
You can then polish, apply lacquer or whatever you wish to do.
Other than that, you could go to a metal treatments / finishing shop and ask them to do it for you (unless you know someone who works there
)
I hope this is of some help as I'm not a typist and it's taken fekkin ages to do
