Jugs of water are often used in the Cooking skill for making wine or god wine. Because of this there is a high demand for it. One can cast Humidify on an inventory of jugs to turn them into jugs of water. Use astral runes and equip a steam battlestaff to maximise profit and efficiency. Set up one of your "Quick Presets" to Withdraw 27 jugs and at least one astral rune, cast the Humidify spell, which will cause the whole inventory to turn into jugs of water, open the bank, Click the Quick Preset and repeat. When playing at maximum efficiency, up to 780 spells can be cast per hour, for 21,060 jugs.