Cermark and galvanic corrosion

I just found out the hard way what NOT to do with finished but unwashed Cermarked stainless: Let water get between stacked plates and just sit there for hours.

About 5:30 this afternoon I was washing off a batch of rather large stainless ID plates. I set about 10 plates in my big laundry sink, and began washing and rinsing each one. With 6 plates to go the wife rings the dinner bell and up I go to eat. Then fall asleep in my recliner for awhile. Then finally head back downstairs around 11pm to finish up. Normally I would have pulled the plates apart, stood them up along the edge of the sink and give them a quick rinse first. Tonight I was flat dead tired and hungry, and didn't...

When I started pulling the plates apart I immediately knew I was in trouble. The plates had many blotchy, small black spots all over that I had to vigorously scrub off with a magic eraser and a fingernail to remove... But the worst part was watching all my work go down the drain as I final-washed the plates, much of the black etching just washed off, and now I get to re-etch the things...

The reason for the mess was galvanic corrosion. I'm a boater (see my avatar) and somewhat understand it... I just spent about an hour researching all the anodic index tables I could find, until I found one that included molybdenum (Cermark)... The list includes 92 metals, with magnesium as #1, the most anodic (most likely to corrode) and silver/gold/graphic as #'s 90, 91 and 92 as least anodic/most cathodic. 304 passive stainless (my plates) are listed as #72, and 'commercial pure molybdenum' is #58. While reasonably close on the index, moly is far enough down the list to start immediately corroding as it starts passing along its anodic electrons to the cathodic stainless in the presence of an electrolyte- the water in the sink. This is why my Cermark went down the drain...

and not long ago I found out how fast copper can eat away aluminum after tool engraving a bunch of nickel plated copper plates on my IS7000. I flood-cool any metal I engrave with water soluble cutting fluid, so I had the anode (aluminum table), cathode (copper shavings) sitting in a puddle of electrolyte (cutting fluid) overnight...
Next day I found this- note the copper shavings piles, and to their left, the corroded aluminum left behind...
Attachment 393351

-closeup of the upper section...
Attachment 393352

SO, you guys using Cermark, don't do what I did and ruin a days work!

And keep your metals separated, it's amazing how fast bad stuff can happen!