So I'm about to buy a 2005.5 S4, and there is some junk on the underside of the glass on the "speedometer + tachometer + glass" (hud?). What is this piece called? I'm trying to search for a cleaning solution, but I can't search well because I don't know the name of this part...

Any help?

 

Instrument Cluster..? If you're talking about the whole unit then thats the name of it. Hope this helps!