I always drilled out the baffles then tapped the PCV holes and put in a threaded fitting, or had Ash weld the holes shut before powder coating. Of course this does require a PCV delete, but that was standard procedure at ASH-SPEC. I would keep sand as far away as possible from those baffles if you decide to keep them. Paint stripper and a wire wheel worked just fine for removing any coating that might be on there already without using any kind of blasting abrasive.
This is what I did to my NA. But what would I know... All I did was answer phone calls and emails which is a skill set that pretty much anyone has... right Ash?!
It's been a while but this is what I remember... - 
