The following is written in the lincoln, wheat ears reverse page of the 2008 Red Book; "Dicoloured (brown) or weakly struck pieces are worth less." what is meant by the brown colour; is it the colour of the whole coin or he means the brown spots or areas of corrosion that may affect the coin. Thanks
It means the whole coin being brown(BN) instead of red-brown(RB) or fully red(RD). Areas of corrosion would be an entirely different subject. Corrosion would be considered a form of damage and would significantly affect the value of the coin.