I don't know if it is the same
type of
patina as on Pat's wonderul
sestertius but I know these powdery
patina LRBs all too well. They are common from UK finds and from lower Austrian finds and I have seen some in Balkan finds too. They combine the powdery green
patina with either parts that have stable, hard green
patina and/or a hard thin brown or black dirt layer (which often just sits on more poweder) and/or a
very fine beige layer (which I think is just a thinner layer of dirt on the powder).
I have never
had much luck cleaning them.
Those with only some powder and an otherwise stable
patina can be cleaned normally but often have divots on them after the powder is gone.
I have brushed some of the more powdery ones with soft toothbrush and got all of the powder off but what is left is a coin with very little detail. I even have one of those very soft, large make-up brushes for brushing these (and believe me over forty year old guys get odd looks
buying such brushes) and it can
help gently remove the powder.
I have waxed some just like Randy has and got fairly
good results though I do not expect such coins to survive for long. I worry they will
still crumble under the wax I usually only do this if it is a
rare mint mark or otherwise desireable coin.
The rest tend to sit in my "to do" pile while I await the magic solution to this problem.....
Shawn
