On June 15, 1988, Hastings Manufacturing Company issued a bulletin warning against cleaning pistons using pressure blast machines with glass beads or various abrasive materials.

We continue to see rings with high degrees of abrasive damage even in instances where cylinder blocks have been bored and new pistons used. We see pistons with the rings stuck in the grooves. We remove the rings and clean them with solvent. The solvent is drained through an absolute filter and the residue examined under a microscope. We find glass beads in the absolute filter!

Bead and grit blast cleaning is a highly cost effective and efficient method of cleaning other engine parts such as blocks, heads, and intake manifolds. These parts have many internal passages that are irregular with blind ends and are virtually inaccessible to mechanical cleaning methods. After bead or grit blasting it is imperative some method of cleaning the castings is employed which removes all the cleaning media from the internal passages. Even a minute amount of cleaning material left in an oil or intake passage will be ingested by the engine upon start up and severe damage to all engine parts will result.

REMEMBER - ANY AMOUNT OF ABRASIVE LEFT IN AN ENGINE IS TOO MUCH!

(P78)