Frets sound brittle

[WoodBlues]

I have a Boucher 000.

It's hard to explain but my guitar started sounding a bit like metal, like if the frets were rusty or something.
Is this caused by dirty frets?

[redir]

I'm not really sure what to say... I think perhaps some history and more information might help. Otherwise change the strings and see what happens. Frets certainly have an input on the guitars tone but not anything like that.