Rinsing Hair with Coffee

I am going to try rinsing my hair with coffee as I am starting to go gray. Just a little, it's only a few hairs so far. But also because my locks can get dull-looking. not matte, which is how my hair naturally looks (tightly coiled/curled hair does not 'shine' like straight/loosely coiled hair does) and which I like, but dull. I think it's because I've been swimming in the pool at the Y and not doing a great job of getting all the chlorine out, plus the water there is just hard.

Anyway. I searched google for natural hair rinses because I dyed my locks before using a regular chemical hair dye and my daughter i-bop has colored her hair many times and that stuff smells awful, really caustic. I can't see putting that on my hair ever again. Coffee or black tea is supposed to be a good temporary color boost for brown or black hair, and red herbal teas are supposed to add a red tint. I may do that first, a deep dark red might be pretty on me. I'd probably have to use 2 boxes of tea. I will post pics after I do it! A few links on using coffee as a color rinse:
http://www.hairboutique.com/askkaren/askkaren-10-2001.htm
http://www.geocities.com/Heartland/Prairie/8088/hair.html