Until a few months ago, I had never heard of this product. A friend in Michigan mentioned it, and said it worked wonders in taking out stains. Being the mother of 2 chocolate-ice-cream-loving children, I am ALWAYS on the look out for a new stain removal product. Well, this isn't new, and is in fact over 100 years old!
Although it was created as a laundry soap, a common home remedy was to use it to combat the contact dermatitis resulting from touching poison oak or poison ivy. It can be grated & added to the wash to remove the residual oils left on clothes after touching the plants.
Personally, I have used it only as a stain remover. I spray the affected area with water, rub the soap onto the spot, and let the item 'soak' for about an hour. My best results come when the garment stays damp, and I commonly only let it 'work' for about 15 minutes before starting my wash. It doesn't work on every stain (if you know a product that does, PLEASE let me know!), but I'd say I get great results 8/10 times. It has even taken away/ faded old stains!
Fels Naptha has a strong smell, and I store it inside a ziploc bag in my laundry room. Because of the smell, I also keep the paper wrapper on the bar, only peeling away as much as I need to expose the surface the soap to the garment. The bar is quite hard and I expect to use about 1 a year. I found this in the hand soap aisle of the local Meijer, but have also seen it grouped with the laundry soap at Walmart. Best part: It retails for about $1.00!