Removing Blogs from Toolbar

I have users on my multisite who were once Contributors but have now been downgraded to Subscribers. When they are promoted to Contributor, the blog is added to the new toolbar as one of their listed "sites". I've now downgraded their status, but the blog still stays listed on under their "My Sites" menu on the toolbar.

Is there a way to remove this listing on on their toolbar? It's not imperative, merely housekeeping.