Bikini Wax - S2-E18
Corrected entry: When Tony brags about how much his tie costs, Kate comments that it's no secret how much Tony makes because they all work together. But in "The Truth Is Out There" in season 1, Tony refuses to share how much he makes, claiming it is a personal detail.
Correction: Some time has passed since that episode so there is no reason Caitlin could not have found out in the time since.
Ssiscool ★