Made nine black glass hex beam dumps today.  Only stopped because we ran out of hex bases.  Need to order more.
Cleaned the glass days ago with the Branson 8200 ultrasonic cleaner.  Wiped down with methanol to remove water evaporate residual.  Have enough black glass for at least three more hex beam dumps, plus some weird big ones or ones with holes in the middle.
Will now dump all beams in transmission with black glass dumps.  Hope to see some reduction in the scatter shelf, but not optimistic since we think the main scatterers are coming from the windows of the vaccan.