Keep it or replace it?
I just received a pair of 2008 Bald Eagle half dollars in NGC grades, MS and PF 70. The proof is already toning. Is this desireable? Should I replace it? Should I protect it from further toning(Intercept Shield), or let it go on toning? I keep all my coins in Intercept Shield boxes to prevent this, but I need at least another opinion. See what you think.