Saddles to start with, if you have steel you could try a Gotoh bridge which IIRC has chrome plated brass...
I bought a Gotoh GTC-101 bridge (strat type) which is supposedly brass and that's the one I'm having issues with.
I've ordered the originals which people said zapped their tone on a strat (something which is subjective but it should solve the high frequency spike problem). The classics are meant to give the same performance without any loss of tone. I think they do look pretty cool, but probably won't do the job I need them too.
Again, I'll let you know on Sunday/Monday how things pan out as I'm currently a couple of thousand miles away from home!