Sentence:  He would have called the man by his first name and said, Not at all, so and so, but though he was very good at remembering names where clients were concerned, there was something very <WSD>Teflon</WSD> about these guys and nothing about them was sticking with him. 
Meaning of the word marked with <WSD> tags:  Having an undamageable reputation (by analogy with nonstick Teflon surfaces).