Our main hesitation with using lye is environmental. This is something I plan to research more. It has been around for a long time and is somehow made from salt. It seems to weaken as it sits in water over the weeks. If anyone knows more about this please contact me .
Commercial lye works wonderfully well.
I prefer it over hydrated lime any day of the week. My first choice is wood-ashes. This quality is excellent for moccasins, bags or anything you don't want to be stretchy. But when you don't want this quality, limit soak times to a week. The effect gets more pronounced the longer they soak.