Electrasol 3 in 1 Dishwasher Tabs
I've tried this for removing olive oil, and it seemed to work very well and safely.
I'm going to do two experiments simultaneously here. The first is to see if it will remove Renwax safely. I have two coins that need further cleaning, but I had Renwaxed them. The smaller, black coin I believe I repatinaed using Jax Black Darkener.
The other experiment is to see how it will remove dirt. These coins have been in my contraption for a couple days, so most of the loose dirt has been removed already. Coins were weighed when semi-wet, as well as scanned when wet.
If this holds promise, I'll break down and buy some standard grade coins to test fresh coins. With the holidays coming up, and purchasing equipment for further experiments, I was trying to hold off on buying any coins until next year...
Coins weigh a total of 72.9g, including the two Renwaxed.
The coins that I pulled seem to include a good spectrum of variations. They have false patinas, partial patinas, a couple different encrustations, compact clay to rich mud... it should be a good test of a good representation of uncleaned coins.
I will boil them in distilled water and 1 tab for about 30 minutes, at a low boil. I will refill the water and add another tab, and reduce the flame a tad more for another 45 minutes or so. I may have to add water to it, while it evaporates.
Before scans:
The two coins with Renwax above
And the two before scans of the dirty coins above.
The coins now weigh 72.6g, and the water was a dirty grey. But... only 0.3g were lost. Scan of coins were done when a bit drier than before, but still damp.
The coins have a lightish residue still left on them, probably due to the cleaning agents of the tabs. The silver brush seems to remove it easily enough.
Renwax was removed easily. I got the idea of just basic hot water, for removal of Renwax, after taking a shower with my Roman rings on. Four layers of Renwax were removed. I think basic boiling water would remove it easily enough. I'm not sure why all the methods I've seen require a chemical of one type or another... when it looks like heated water would do it safely.
And the after scans:
Overall, not much difference, though there has been some removal of dirt. Offhand, I don't see any loss of patina. The Fel Temp of the Renwax may have lost some on the obverse, but it was patchy to begin with. A small amount of encrustation has been removed, but it wasn't much, and the remaining encrustations don't seem to be softer.
Minimal success... still works great to remove oil though, without using harsh chemicals like TSP.