Get a 5-gal container of cleaning compound (purging solution) for the M978-series HEMTT fuel tanker with NSN 7930-01-350-7034. For a 55-gal container, use NSN 7930-01-350-7035. You’ll find it listed in ATP 4-43, Petroleum Supply Operations.
Make sure all purging solution is removed from the tanker before deploying, shipping overseas or sending to RESET. Follow the procedure for gravity bulk unloading of fuel from the tanker. You’ll find it in the operating instructions of TM 9-2320-279-14&P (IETM EM 0290, Jun 09) for the M978, TM 9-2320-325-14&P (IETM EM 0289, May 09) for the M978A2, and TM 9-2320-326-14&P (IETM EM 0288, Dec 15) for the M978A4.