Gris to the mill

Posted by Mike Hands on June 10, 2004

I have heard the phrase "gris to the mill" hundreds of times in the West Midlands. My understanding is that it means 'more evidence' or 'something else that helps' or something like that.
Does anyone know where the phrase comes from? I guess it originated in the northern mills, but it would be great to know the real origin of the phrase.