Pluto exalted in?

Its Leo.

Okay, I was hoping it'd be Aquarius.

I have Mercury in there and I had planned on doing workings for intelligence or my mind when Pluto was transiting.

I'm assuming that it would be harmful to do that?

You can still do workings to improve your mind and intelligence when Pluto is transiting your natal Mercury. Pluto in Aquarius is not malefic. Pluto is a neutral planet. Pluto in Aquarius is just less powerful than Pluto in an exalted or home sign.

Okay, thanks for the help.