I've used lye to darken cherry. But I really think it's unnecessary. Cherry will darken pretty quickly on it's own. And when you use lye, you're using water so you raise the grain and then have to sand when it dries. If you sand too much in one place, you'll take off the dark wood and expose the natural color. The darkening only occurs in the outer layer of the wood.
I didn't find working with lye to be a problem. The lye is the same used for opening drains. Just use gloves and good ventilation - do it outside. Better yet, don't use lye and just put the project in the sun for a day. You'll be surprised at how quickly it darkens. Note that sapwood does not darken so the contrast will be stronger after you age it.
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