Using bar soap to make body wash is a thrifty way to save money since shower gels typically cost more than solid soap. It will also reduce your impact on the environment because you can recycle a plastic bottle to use as the body wash container and you won't produce any waste that's normally created by packing commercial soaps in paper, cardboard or plastic. You can make a "pure" body wash scent by using only one brand of soap, or you can combine various bar soaps for a distinctive fragrance.
Slice your bar of soap into seven or eight long pieces on the cutting board with a long cutting knife.
Chop each long piece of soap into bite-sized cubes.
Put the soap in a blender.
Set the blender to chopping speed.
Let the blender run until the soap is thoroughly chopped into small pieces. You might have to occasionally shut off the blender and loosen the pieces with a plastic spatula to get the slivers completely chopped up.
Add 1/2 cup hot water.
Set the blender on a speed that will gradually blend the soap chips with the water.
Let the soap slowly blend with the water. Keep an eye on it while it's mixing. The goal is to have the contents achieve as much of a gel-like consistency as possible.
Add a few ounces of hot water as needed to keep the soap blending easily. It's better to add too little at a time instead of too much because if too much water is added, the soap will become liquified instead of turning into a gel.
Shut off the blender when the soap reaches a gel-like state.
Put a funnel in the top of an empty plastic bottle.
Scrape the soap gel from the blender into the funnel.
Screw the cap on the bottle. Keep the bottle of soap sealed between uses to prevent it from drying out.