If you want to make soap you have these basic choices:
Cold process (CP) soap making which involves handling lye directly, mixing it with water and fats, and getting soap on the other end. If you make it properly, the lye will be converted into soap (a form of salt) and there will be no lye left in your finished product.
Hot process (HP) involves the same ingredients as CP and also requires handling lye directly but you heat the soap mixture in a crockpot, in the oven, or on a stove top, which speeds up the chemical reaction of turning lye, fats, and water into soap.
Melt and pour (M&P) soap base is sometimes detergent based and sometimes CP based; if CP-based it involved lye in its production. You're not really "making" soap, you're melting it down, adding color and fragrance and letting it harden again. Beautiful soap can be achieved using this method.
Handmilling or rebatching soap. This involves grating up existing soap (CP or a commercial detergent bar like Dove), heating it, and then mixing it with the color, fragrance, or additives of your choice. You wouldn't handle lye directly with this method because it was already used in the manufacture of the soap you grated up.
Hope this helps.
Edited to take carebear's comment into account. She's right; that's what happens when I type too fast.
