Good to hear of the improvements.
The book is only available free by download, Precision Aqueous Cleaning of Vinyl Records-3rd Edition - The Vinyl Press. Bill Hart @whart runs a tight ship as they say, and I can only guess that the book (pdf) has been downloaded many, many times with no one ever indicating any malware or virus. The document was scanned for viruses and malware before being posted and the (my) computer that was used to write the document has a very high cyber security posture and the book is password protected from making any changes.
If you download the book, before opening, with MSWindows you can right-click and there will be an option to scan the document for viruses/malware.