[MikeK]

Hydrogen embrittlement occurs when Hydrogen forms at the surface and penetrates the grain boundaries of the alloy. This occurs both in electro cleaning and plating operations. The result is micro expansion of cracks over the next few days. Think of it like water getting into a tiny concrete crack and freezing. The crack opens. Likewise with the metal grain boundaries.

Used parts with micro stress cracks will fare the worst. I would avoid the process on any grade 5 or 8 fasteners, springs, weldments, drive shafts or axles, and suspension components. Used sheet metal that appears OK may develop cracks if flexed, like the fenders in the bead area over the wheel. The hydrogen can be removed after your process by baking the parts @375-400F for about 100 hours (yes, 100!) You need to begin the baking within a few hours of completion of your cleaning process. Extended electrolytic cleaning, in excess of 24 hours may cause unrecoverable damage.

For non-critical parts an acid neutralizing rinse followed by heating the parts to 300F for a few minutes to dry them will be fine.

SAE AMS 2759/9 spells out the procedures for embrittlement relief.