Polyvinyl acetate is not water soluble, it’s most likely polyvinyl alcohol, which is.
My print head reject rate is pretty shocking. Seems like the older ones work better than newer ones. I just had a newish one (from 2010) crap out during its initial purge. Maybe I need to spend a day cruising thrift stores and hope for a big score, these are way too expensive to throw away without being able to use them even once.