During my RAF days it was by no means uncommon during tasking with the army to self refuel our helicopters with AVTUR from drums. The drums had to be allowed to stand for at least an hour after delivery so that any water or debris would settle. We then had to draw a sample using a tube that reached the bottom of the drum and use a test capsule on a syringe to confirm it wasn’t water. The capsule would turn blue if contaminated, remaining clear was good. I also discovered that it was possible to look down to the bottom of the drum using my flameproof torch where any water or debris could be easily seen. It was by no means unusual to see a small puddle of water.
We carried an electric pump which sat on top of the two inch bore aluminium suction tube, powered by the aircraft battery. The tube pickup assembly had a rubber buffer at the lower end and it was designed to leave a small amount of fuel behind, along with anything undesirable sitting at the bottom. It came on a tubular aluminium frame which held a filter. It was a fairly large piece of kit and we had to deliver it to the refuel point at the start of the tasking day. I often went back to base stinking of jet fuel; I don’t recall being supplied with protective gloves or anything else.