i think ICG downgrade much coin as much PCGS and NGC do, and that 1940 Pfennig does not show any type of env. damage and it looks much better than ms60 condition
White patches on zinc coins are the start of corrosion and can easily be described as environmental damage. Those coins are very environment sensitive. Your coin has white patches. AU-MS zinc coins do have a form of luster on them and show dark patches where the luster is wearing thin. See the difference... http://img.ma-shops.com/weller/pic/h2472.jpg https://img.muenzauktion.com/pollandt/pic/artid10880_combined.jpg You've already seen this topic with photos. I don't see how your PCGS coin looks the same as this ICG one... https://www.cointalk.com/threads/german-nazi-coins.198534/
Your 1918 10 Pfennig seems to be correctly graded . I wonder if they can be conserved to protect them for future generations .
What about bronze coins ? MS BRN MS RED MS RB ?? SAME AS ZINC CHANGING COLORS ARE NORMAL FOR THIS TYPE OF METAL . CHECK THIS OUT GARBAGE COIN GRADED AS MS-62 BY LOVELY PCGS BELOW
MAKE ME WONDERING : WHERE IS DETAIL GRADE FOR THIS ONE ??? AS SCRATHED. SO MY BOTTOM LINE IS ALL TPG GRADERS HAVE LACK OF KNOWLEDGE WITH EXPERIENCE AVERAGE FOR 20- 30 YEARS ALL MAKE SAME MISTAKES , THE ONLY DIFFERENCE IS WHO MAKE & HAVE MORE $$$$ TO ADVERTISE THEMSELVES AS TRUSTED MORE . TO ME THEY R ALL THE SAME
Maybe for world coins , but there is a big difference in the tpgs for US coins . PCGS and NGC are the top 2 .
Nice to know I might have a binder full of MS quality zinc coins. That's why, the country of origin should set an example for the world, as to the standards that apply to their unique coins. Blaming the US for not knowing as much or caring about world coin submissions is a bit strange. With their internal TPG competitiveness and bickering, they have done more for the hobby, than any other country. I see no reason to complain. It's the other nations that should make an effort, keep up, or shut up. At the moment, Polish-Indian PCG is your available alternative. Send your coins to them, with a request, telling them what you'd like to see written on your slabs. I'm sure you'll be happy with the results. I like placing significant importance on original luster, zincs included.
I think this is all about market acceptability. Both those coins (post 49 and 53) have significant enough corrosion which would make them details coins IMHO. However, with this series being so prone to corrosion, I think the TPGs are willing to be a little more liberal with their grading. If the market will accept it, they will do it. Personally, I wouldn't want either of those coins in my collection as I consider them damaged. There is a difference between toning patina and corrosion. Here is one from my collection. It has a little toning on it...but the metal itself hasn't started to be damaged. Yes, toning is the first step of corrosion (as it is oxidation) but with proper storage it shouldn't progress to where it damages the coin.