What explanation can there be for the low levels of traces, and absence of blue staining, in the homicidal gas chambers?

2) If one suggests that the Zyklon traces in the homicidal gas chambers have been "weathered away", how can one explain the traces and staining on the OUTSIDE of the delousing complexes...traces which have NOT been weathered away after fifty years? 3 ) It has been suggested that the amount of Zyklon B needed to kill people, even cumulative millions of people, would not leave traces as strong as the amount needed to kill lice in the delousing chambers. But when we factor in the Zyklon B traces still existing in the camp barracks and offices, we see that infrequent gassings will still leave SOME traces. Thus, we have the traces in the camp offices and barracks, which reveal what levels of traces would remain, fifty years after the fact, in rooms which were gassed infrequently. Then we have the delousing chambers, which reveal what levels of traces would remain, fifty years after the fact, in rooms which were gassed frequently. Can it not be expected that the levels of traces in the ...  more