Long-term storage & reuse of Mag Plates

I have another newbie question about magnesium plates. I have seen old magnesium cuts that have “corroded” (with white powder & stuff appearing on the plate surface).

Looking at some discussions here at Briar Press, the suggested method to prevent (slow down) this corrosion is to apply oil lightly on the plate surface:


I have a couple of questions:

(a) Can I use motor grease instead of motor oil?

(b) How do I clean the oil or grease off the plate when I want to use the plate again? Can I use a de-greaser, and if so will it ruin the plate surface?

(c) Can I use WD40 as a de-greaser for the mag plate?

(d) Will traces of the de-greaser impact the ink?


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Keeping moisure away from magnesium plates is the key to longevity. A quick spray with a light cooking oil will work and if you can place the plate in a “baggie”after oil, it will last that much longer. Grease certainly would work just as well, anything to cover the surface to seal it from moisture in the air.

Simply use press wash or type cleaner (whatever you intend to use to clean up after printing) to remove the grease or oil from the surface. WD-40 is not a cleaner, and does contain some silicone, so should not be used in the pressroom while printing or prior to printing.

If you want to use grease, why don’t you use petroleum jelly, that you can buy at any drugstore? Who knows what is in automotive grease, but since people use petroleum jelly in contact with their skin sometimes, one would think that it is less toxic. I haven’t done it, but it seems like a reasonable idea.

I’d recommend something along the lines of Vaseline (petroleum jelly) and mineral spirits or Simple Green as a degreaser.

i’ve never done anything to my mag plates, after 40 years i have only lost one or two dozen at the most, when they start showing signs like they are going to corrode i use an engravers rubbing stone on them to clean them up. if they aren’t stored in a heated environment they will corrode very fast, if i were going to do anything to them i would spray them with silicone, or a light oil, in my shop i have about 100 galleys of mag dies, some are 40 years or more old. Dick G.

I oil them, bag them, and then put them in a labeled envelope. They are unmounted.

Thank you all for the help & wonderful comments.

Vaseline (or petroleum jelly) sound much much more attractive than motor grease that I had in mind :-)

And placing them in bags (zip-lock) and enveloping them is a great idea.

Thank you all again.