Here is what the valve looks like:
http://www.appliancepartspros.com/part_details.aspx?part_id=3094541&image=1
$10 to 20 part. I will see if I can clean it. Cleaning the screens now.
I’ll bet if you drop it in a bowl of CLR for a while, you will see all kinds of crud come out.
Should be some white flakes, maybe even chunks.
Take a toothbrush to it. If you have a bottle brush that would really get it clean.