STEAM CLEANING
I have had this idea for awhile, and finally bought a strainer. I wish I had a steam cooker like I did when I was a Sous Chef, but this will have to do.
These coins have been soaking in my contraption. There shouldn't be any weight gain due to water gain, and all loose dirt should already be removed.
The coins begin at 47.7 grams. There is a nice assortment- dirty, mud caked, encrustation, patinas, no patinas, weak patinas, and dusty.
I will bring a pot with distilled water and bring it to a boil. I will insert the wire mesh strainer, which holds the coins above the water, and cover the pot. I'll let it go for at least an hour, and check the water level occasionally.
The premise is that the steam should be able to permeate through the dirt, even more so than soaking, and hopefully loosen up the dirt. I don't see any harmful side effects possible... so let's give it a try. Before scans below:
I steamed each side of the coins for about an hour each. The water was slightly dirty, so some dirt has been removed- but not anywhere near as much as I had hoped. Coins now weigh 47.8 grams... a gain of 0.1. I didn't expect that.
The coins were pretty much dry when scanned, so the coins either darkened a bit or cleaned a little. Not very impressive and pretty much a waste of time... but at least I know now.