This article is a great example of the investigative work that is required when archaeological evidence and its analysis face mysterious disappearances. Chitra Balasubramaniam has written about how she followed the case of a piece of cotton cloth that "came wrapped around a silver perfume jar and a salt cellar" that John Marshall found during his Mohenjodaro excavations. She traces the specimen to a laboratory at what is now ICAR - CIRCOT — Central Institute for Research on Cotton Technology, Mumbai, and finds the report associated with it.
More on the early history of cotton in India
More on Indus Valley textiles, there's Dr. Jonathan Kenoyer's Ancient Textiles of the Indus Valley Region
Above: A small piece of cloth discovered in the Marshall-led excavations at Mohenjo-daro. He wrote:
"No textiles of any description are ordinarily preserved at Mohenjo-daro owing to the nature of the soil of that place, but adhering to the lid of the small silver case illustrated in Plate CXL, a small piece of woven material was found taht had been preserved by being impregnated with silver salts.
This fragment of cloth was submitted to Mr. James Turner, Director of the Technological Research laboratory, Bombay, for examination, who remarks in his preliminary report that "the fibre was exceedingly tender and broke under very small stresses. However, some preparations were obtained revealing the convoluted structure characteristic of cotton. However, some preparations were completely penetrated by fungal hyphae. The appearance of one of the convoluted fibres is shown in the accompanying photography (Pl. CLIX, 6 and 7 [shown above]). As this examination has been confined to a fragment measuring 0.1 inch in one direction and 0.3 inch in the other direction, these results can only be regarded as tentative." [John Marshall, Mohenjo-Daro and the Indus Civilization, p. 585.]