Post damage in Paragay coins, a mistery

Hello experts, 

Some time ago I talked in my whatsapp group about coins from Paraguay from the 1950's  that happen to have post mint damage, for my surprise a lot of people have ou have seen those coins with the value scraped off, few still keeping them but today I found a guy who collects them and again several people said they have seen that.

I searched everywhere online for any literature about what was for, no clue.

The coin is this one:

N#5146

My theory was that, since the 25 centimes was only 2mm larger, and the coin was scaloped, they could pass as 25 in the change. Just a Theory. 

The coins are always damaged in the value side, always same method, the tool that made the damage are different in some coins. These damage was found in different places of America, so it is not all from same source.

Just one photo of a collector but I have seen several.

Any information or literature for what  is that damage for? 

Maybe the Referee knows something about it? @Dieter83 

Thank you for any comment

Geison

Hi Geison,

Thank you very much for sharing your pictures.

Possibly these coins falling into disused due to its low fractional value and it had a "second life" later as internal control tokens in some livestock ranch/establishment. That's could be the meaning it has a punch at the center that even in some coins seems look like a symbol, being more a countermark directly.

It was cheaper for these establishments to punch existing coins than to produce new tokens.

Punchings outdated coins or marking them with letters was a practice that can be also observed in Argentina and Uruguay too.

I copy these 2 examples below:

Uruguay:

N#335471

Paraguay:

N#361439