Occluded Gas
Occluded gas occurs when there is reside on the surface of a coin from the wash tank. The gas resides escapes when the coin is plated, creating bubbles on the surface of the coin. More familiar to the late 1980s, when the mint was experiencing cleaning issues from the wash tank. Although not as common, there are coins dated in the 1990s and after with occluded gas issues.
In the first photo is a 1982-D Lincoln cent with extensive gas bubbles encapsulated by NGC. The second photo shows a rare 2021 Lincoln cent with occuled gas.
Stan McDonald - Author of error coin guides
Comments
thatcoinguy
Level 5
Do these have any numismatic value?
Stan McDonald - author
Level 4
Under $10, even in a certified holder.
Kepi
Level 6
Really interesting! Thanks! ; )
CoinCollector7777
Level 5
I think I had one with a dot... I don't know for sure.
coinsbygary
Level 5
You're right about this problem on proof coins. I have a 1984-S proof Lincoln Cent with this problem, and I have always wondered what caused it. Now I know. Thanks for your post and explanation. Follow this link for a picture https://www.ngccoin.com/registry/competitive-sets/73886/coins/600020/
It's Mokie
Level 6
I think Steel Cents also suffered from that malady.
Stan McDonald - author
Level 4
Steel coins rusted after a few years. Most of the BU samples you will find have been resurfaced.
thatcoinguy
Level 5
Man, that seems like a good starter error for all you beginner roll searchers out there. Great blog, thanks for the info.
AC coin$
Level 6
Interesting nice coin never see proof example. thanks good blesse
"SUN"
Level 6
Good explanation of the problem
Golfer
Level 5
Interesting issue for coins. Minting coins has many potential problems. Thanks
Haney
Level 4
Yes those early plated cents did not hold up well and half the time like your specimens they never had a chance. I have even seen proof examples with gas bubbles.
Mal_ANA_YN
Level 5
I see those every day.
Longstrider
Level 6
Nicely done. I have seen less nasty examples. Thanks.
Well worn Copper
Level 5
Looks like Abe walked into a swarm of flies.
Mike
Level 7
These I have seen. Going back to 1797 half penny's made in Britain. And here.