If you did the STE by the book, and at 85C some white precipitant began coming out, I would think from past experience you were seeing psuedo starting to precipitate. Pseudo does not precipitate out at 90C. By 90C all the pseudo will have precipitated out. You will see pseudo begin to precipitate out prior to 90C, as the alcohol content in the solution becomes too saturated to hold the pseudo HCl in solution. The naptha should hold the lower weight PEGS (i.e.PEG 400) in solution at the temperatures we discuss here.
Finish heating to 105C and filter hot, rinse with MEK or acetone.
Then, if you have questions about how clean it is, dissolve it in hot ISO and preciptitate it in fresh xylene or a mixture of fresh naptha and xylene. You will find that a "xylene clean" of STE extracted pseudo will remove most gakks that got through with the pseudo in the STE.