While I am unsure of the sources for this (it was part of a phd candidate's presentation, though I am sure I could track it down later), in medieval Iceland the church levied a tithe, which was usually paid in butter. The butter was so heavily salted as to render it near inedible. At one point, the church had amassed several tons of it. In order to render it edible again, it would be soaked in water so as to slowly dissolve the salt out. The purpose was somewhat vague - it appear to have been a stockpile in preparation for a period of possible deprivation. In medieval Iceland, this was always a serious possiblity, given the lengthy winters and relative isolation from imports. In the instance of a particular surplus, the church could sell it, or exchange it for goods they needed.