Netherlands 5 Cents 1978 - Weak strike or ??

[$and€r]

I bought some kilograms of Dutch coins last week.. with the purpose to try to find doubled dies .. 
Now i found this one, but i never have seen or found this before..  Although i have a faint memory that i have seen this maybe once on a forum.. but not sure.. 
First i thought maybe this coin had some acid bath or so.. But then the edge should also be affected, and it's not..
I'm pleased to hear your thoughts.. Many thanks in advance.. 

To compare i attached also the "normal" 5 Cent 1978 photos.. 

[Figleaf]

This didn't happen in the mint. The coin spent some time in an unpleasant place, but another coin (I think it was the same size) was on top of it and shielded it from more damage.

I think the damage was done by an acid. My favourite culprit would be a raw herring seller. Hands soaked in vinegar, coins ready to give as change, but accidentally shoved into a forgotten corner. However, lying around in a room filled with coke (steenkool) steam will also do the trick, albeit slower and perhaps more gradual.

Take another 5 cents and put it on top of the damaged one. Shove it around until you see only the worst affected part. That damage may have been caused by a liquid acid. Note how because of the edge on both coins, the lower coin is largely protected from liquids, but not from vapours. Imagine the acid slowly dissolving in air, some of it getting in between the two coins.

Peter

[africancoins]

It rather seems to be one of those coins that has been through a (proper) recycling system.

Eurocoin has told us about this before.

Thanks Mr Paul Baker

[$and€r]

I think now after some research..  it's a so called "dryer coin"

[Thulium]

I agree. This shows in the rims; they have been rounded down by rattling around in a commercial clothes dryer for some time. This also produced the soft/rounded details on the portrait.

I think now after some research..  it's a so called "dryer coin"