i can't seem to get an image back to grayscale mode when i remove the duotone settings, the image will take on the luminosity of whatever spot color was being used and i want to avoid that...

I see what you mean. Is it better to convert to RGB, then choose the best channel?

i think it may just be to make sure the curve isn't alerted and then choosing a black for the spot color and then removing the duotone setting, i'll have to post the same message on the adobe board...

You can't just switch it to monotone first? I did some quick tests and that worked for me. Otherwise it's doing exactly what you ask of it, just as if you'd moved from RGB to CMYK.

even in monotone it keeps the luminosity of whatever color you are using, even when i use solid black with the color picker...

How strange. I deliberately tried to muck it up, but it simply deleted the 2nd duotone channel when I converted to monotone. Perhaps your first channel was not black?

it wasn't black, it was 2 different shades of brown and i wanted to see the range of the graycale image the client had supplied..

I didn't think anybody used duotone mode any more ...

neither did i, but we got some files from a client in that mode and we have to match other files to that look...