Yesterday
Spent time on tool autopsies, re-cleans, and re-assemblies. We did not find egregious hydrocarbons in any of the usual nooks and crannies. All six drills were reassembled, deemed ready for use since they all spun when turned by hand.

Today
Morning check-out of hoses, compressors, tanks, etc. Ran spin checks on all six drills prior to going into chamber. Four out of six drills appeared to work at the time (1, 3, 4, 5). However, when put under load in-chamber all but one failed to function. Apparently, drill 5 (also known as "5 of 6") comes from some foreign planet that allows it to run regardless of the severe abuse heaped upon it by the demands of aLIGO chamber cleaning. We will spend the afternoon working on tooling again. (We'll see whether we can figure out what characteristic "5 of 6" has that the other drills do not and we will play with the surgical drill.)We cleaned two sections today and determined that a "pouffy" brush works pretty well on chamber walls (gives a more uniform finish) and the LLO-designed chuck replacement and small cup brush combo works well close to the fins. We brushed two sections today, bringing the total sections cleaned in BSC-7 to 18 of 72 or 25% of the chamber.