Tracy,
When you refer to "turn white" do you mean non-greyed out and enabled again? Method has an Enable/Diable Field/object action which greys out fields(Disables them). As far as changing color goes the only option at the moment would be if you are using a label and it would require updating the content of the label to have HTML to change the color.
-Michael
Michael Melo
Product Manager
Method Integration Inc.
Website: http://www.method.me
LinkedIn: http://www.linkedin.com/in/MichaelMelo