both liver & kidney are filters, I`m related to a award winning chef (seriously) & one day in his restaurant kitchen I asked what was sat in 5 or 6 large pots on the stoves? he replied Oh we`re doing a kidney special this week so we`ve got to clean all these before I can cook them

I stood stupidly looking at him like he`d just spoken Swahili
he explained that liver & kidney need to be soaked to clean the - ahem- whatever- is in them to come out before you cook them, now, fortunately for me I detest both long before I had this conversation, so it doesn`t matter to me, but, looking at BBF`s comment on `food` reminded me, thought I`d share.
sorry Ray, just thought you all oughta know!