Glass and Sterling Overlay Salt Shakers Mark?

[chrismittty]

I recently got four of these and was wondering if any one was familiar with the hallmark or maker? They need some TLC but are absolutely beautiful if you ask me. Looks like " L H M" maybe? with Hecho en Mexico and D. F


The Shakers:


And the mark:



Any ideas fellas?

[chrismittty]

Also, Since it clearly has some salt or other HEAVY tarnish and or almost rust like damage, that polishes somewhat, What can I do to safely clean these puppies up being quite fragile with thinly sheeted silver overlay..? Im talking some Deep brown Textured Tarnish. Devilish looking stuff.