What makes old nickels red?

[wheatfinder13]

I always find the red nickels what is that and is there any way to get that off? Thanks

 

[detroitdigger]

It is because of the copper and nickle mixture

 

[looking4largecent]

I tumbled some roached out buffalo nickles that were red and they turned out nice I used aquarium gravel hot water and a small amount of soap in a rock tumbler.

I always find the red nickels what is that and is there any way to get that off? Thanks

 

[matt092079]

Because they embarrass easily.