All I found was an archived article from Sep 1945 stating that they were still at the base camp eight weeks later. All the material mentioned (labware, trinitite, a contaminated truck) was bulldozed into a trench and buried. I think it was trench B at T-21 or something similar. The trench was big enough from the aerial photos, but I haven't found any references to disposal. I found a site with lots of photos of them (labeled British something) and a debate over whether the number two tank was silver or not. Lots of related info, but nothing about where they got rid of them. Did you ever call the number suggested on that website? I'm sure there's somebody at LANL with a clue to their fate.