The development and initial testing of a novel hot gas clean-up system has been previously described. It utilizes glass coated refractories arranged in various configurations to efficiently capture and dissolve fly ash particulates in a continuous manner. Some tests were performed at room temperature which were intended to be for reference purposes with low collection efficiencies expected, but instead they showed very high particle collection efficiencies. Both the room and high temperature tests raised questions about the role of the glass coating versus the role of the internal components and design of the apparatus in the particle collection process. This report contains the results of studies conducted primarily at elevated temperatures with clean, (new, non-glass coated) refractory internal components. Initial results also indicated rather high and unexpected collection efficiencies. However, the use of a glass coating provided even higher collection efficiencies; up to 99.9% of the Exxon Mini-Plant No. 2 Collector fly ash-limestone mixture, which are believed to be indicative of the real value of the glass coating and glass filled bubbler. Results indicate that: (1) The high efficiency, low temperature results are due to electrostatic charges on the particles especially in an insulated test apparatus. (2) The apparent high efficiencies at high temperature, without glass coatings, was due to agglomeration and sintering of the fly ash as it passes in or near to the oil burner flame. (3) High efficiencies with glass coatings were again demonstrated in the last runs by preheating the test apparatus to get the glass to a sticky condition, then feeding fly ash.