Cylinder head bolts

[Martin Benade]

I saw some videos of it, seemed to go pretty slowly. I believe it may be extremely fine abrasive particles in a liquid or vapor. I have no idea if it can leave bad stuff inside, but it sure looks nice.

[Ron LaDow]

From Richard's link, 'vapor blasting' certainly does contain (undefined) 'abrasives'.
From old fart memory, Ted at German Precision used walnut-shell blasting 'abrasive', which I guess could still cause damage to a lead-surfaced bearing, but not much else.

[Steve Hatfield]

I’ve had good luck with soda blasting at my local swarf shop.
Take a look: