How does one delete a material from the prt once it has been assigned to a prt so that I can visualize prt color operations again?
If you mean “PRT Loader”,then just like with any Max object, you either drag and drop a None material to it (in Max prior to 2011), or you select the PRT Loader and type in the MAXScript Listener
$.material = undefined
There is a UVW Remove utility under the Utilities tab > More… that has the option to remove materials from selected objects. This is the approach in 2011 and higher now that there is no “None” material in the Material/Map Browser.
There is also a checkbox to ignore the material in the viewports if you want to render the material colors, but don’t want to see them in the views.