Can I use "spent" lemons (juiced) to preserve? I'm about to juice 5 or 6 lemons, I'll zest maybe 2 of them. (I'm making a lemon cheesecake). Lemon isn't something I care to use very often, but I'm intrigued by 'preserved lemons', something I've never done (always a plus). It was cheaper to buy a five pound bag of lemons (11 total) than to buy 6 lemons individually, so I'll have 5 or 6 left over. Obviously the juiced and zested lemons are trash, but what about the intact rinds of the juiced lemons? Can I shove those in the jar with the salt too, along with my 5 or 6 remaining lemons? Or will that throw off some kind of magic ratio?
Here is a recipe that i tried a while back. I wasnt too impressed with the spicy one. But overall good method and clear explanation. And sure get your extra zest in there too! 

http://awesomepickle.com/make-pickled-lemons-two-ways/