Sometimes. Most of the time. I have opened a used soap before and found mold growing inside, and have seen others post around the internet of such findings. The fungus is among us. Sometimes. If I receive a used soap, open it and visually can't see anything wrong, I still scrape off a top thin layer.
Certain components can go rancid, like almond oil. With the trend of artisan soaps going full fatty with few or no no preservatives, that’s not surprising. Used soap threads pop up on the forums every few months, and my advice is always ‘If you have to ask, the answer is no, don’t use them.’
I will tell you! A few days ago I received a PM with someone wanting to sell me some "Barely used blades"!
Absolutely! In retrospect it was the best thing I heard because I mentioned it to one of my friends on this forum. As a result we're sending each other a couple of Tucks that will give us each a chance to try blades we never tried before so it's all good.
my turtleship pine soap had a huge black spot over and under the pine tree chip. in the tub.tossed it..used twice..