dana,n, Sorry for the issue of providing a usable plate is so troubling.
I did send the info over to a Chemist who I know and gave him the PLA filament as an example. I did not want to ask him to check all the the filament types. Given that no filament type has been called out by BL to this point.
The very short chemical answer is: IPA is the idea solvent for PLA. Choosing a non polar detergent will also work but it will have the historic issue of not being able to be completely removed it from the plate. I believe Dawn is a blended detergent so it has the non-polar detergent performance.
I am not a chemist my generalized repeat of how the cleaning works:
In all cases the cleaning is a solvent base method, there is no breakdown of the composition of the materials to be cleaned, which was suggested as a benefit of using a detergent.
My guess is that folks are having trouble with the cleaning of their printer plate which is more based on how well they clean and how often it is done. I believe that some of the print failures are from poor cleaning if not a lot of the failures.