Many Thanks to you reply SAP, Actually this effect, only appeared on the 10 centavos in 1998, It was the first year of the second family of Real Plan, There are many and many coins like that or similiar to those showed on the pics. I agree with the excessive use of dies and I believe I have already seen some erosion effects on coins, But I am not sure if this is What We seen on the 1998 coins.



























