He can keep the handkerchief. It isn't the one Jin Guangyao is most attached to anyway.

A small, stifled laugh, a slight inclination of his head, and, "Someday, yes. Perhaps not near this thoroughfare." Just a glimpse of some dry humour behind the layers of courtesy that drape themselves across his every word and gesture. His curiosity is clearly piqued, however, evident in the way he seems to appraise Palamedes for just a moment, hesitating, before he asks, "These wards and your interest in them--is this part of some work that you perform for the protection of Trench?"

Because he rather transparently appears drawn to that. The possibility of a clear avenue for being of use again has gotten its hooks into him.