Say ‘Fels-Naptha’ to your mom or grandma and see what kind of reaction you get. It will probably something like, ‘Oh, yes! They used to use that in the olden days on laundry day.’ Why the bar soap isn’t still popular today is a mystery, because it is one of the best–if not THE best–pre-treater/spot removers on the planet. I know this because I picked up a bar at my local grocery store a while back to give it a try.
To use Fels-Naptha as a pre-treater, you just wet the bar and then rub it on the offending stain. Or, you can wet an old tooth brush, swipe it against the bar and then gently rub the stain with the brush.
Making stuff with it:
My next experiments with Fel-Naptha just might be using it to make my own laundry detergent. Two versions, one liquid and one powder, can be found on Wikipedia, both of which are very cost effective.
Fels-Naptha is available on-line but it may very well be waiting for you at your grocery store too. The cost of one 5.5 oz bar–which will last forever as a pre-treater–will set you back about $1.50 or so.