I suggest you be careful here, sounds like you are insinuating I do something that would be considered unethical. I do work for a few boardies and the reason people use me is good results. I have several customers on the East coast that ship to me regularly. My main focus is conservation and extending the life of comics. The only time I ever use a solvent is during tape removal and even then the final adhesive removal is done with a staedler.
Careful how? I am saying if I had an alleged $60k+ book (or 2) I would not send them to be pressed/cleaned by:
a). A person/entity I have never used before.
b). A person/entity who's main focus is on conservation if I believe the comics I am sending are un-restored/conserved and I wish to keep them that way.
c). A person/entity across the the US border, necessitating a lot of fees, paperwork, and potentially extra hands touching my expensive books.
So, in summary, for me, a logical person, those are a lot of good reasons to have this work done elsewhere, which begs the question: Why did he use you? I don't think there is anything "ethical" in that question.
On top of that, D--- likes to tout his own services, so why not do it in-house?