First thing this morning, John had a look at the rusty water being blown out of the compressors and agreed that it was the result of condensation due to the heat. He gave the go-ahead for work to begin in-chamber but encouraged the crew to continue to be aware of similar circumstances. Particle counts were taken in chamber (chamber with 2 people standing still, drill with metal shroud with no vacuum, drill with metal shroud with vacuum, drill with metal shroud and vacuum while brushing chamber-right side of operator, left side of operator, drill with metal and Teflon shroud and vacuum while brushing chamber-right side of operator, left side of operator). Then, serious work commenced. The crew split today and spelled each other for breaks and lunch. Twenty-six sections were brushed in the chamber and the work on the dome was started.