Wheatpaste is just starches. It just seems logical that it would still be water soluble, is all. I personally have never tried to remove wheatpaste off of anything and dried starches can be a pain to deal with. (Clothes are an exception: you just throw the thing in the wash and be done with it.)

(Of all things I have typed on the internets, I never would have guessed a preliminary analysis on wheatpaste would be one of them. Lulz.)