A couple of months ago, I refilled my soap dispenser from a very large jug of liquid soap (as I’ve done many times over the past six years). After I filled it up, a friend of mine who was temporarily living in town moved out, so he gave me his leftover supplies, including half a dispenser of liquid soap, so I used that up before moving on to the one I’d just refilled.
Only now, the soap smells different than I remember. Worse, in fact, almost rancid, yet I can’t believe that’s what happened, or I’d have noticed it long ago, given the circumstances.
Is there anything to this than just switching back to something familiar after some time away from it? Can soap “go bad”?
. Certainly. The site says liquid detergent lasts a year after opening, and bath gel expeires three years after opening. Dry soap lasts much, much longer because it doesn’t contain water. Any solution of something in water can become a feeding ground for bacteria, and soap (being basically an emulsion of chemically altered fat in water), is no exception. Usually waterbased cosmetics contain preservatives to unsure a longer shelf-life.
The best thing for you to do is to wash out the soap dispenser with hot water and put in your own soap again. Make sure your own soap isn’t too old as well; soap could become a source of bacteria long before it starts to smell bad.