There are four main methods for making soap: 1. Melt and pour, the easiest method, involves melting glycerin soap blocks and adding colors, scents, and herbs before pouring into molds. 2. Rebatching involves chopping existing soap, heating it, and adding ingredients like milk before pouring into molds. 3. Cold process requires mixing lye and oils, adding ingredients at trace, and letting the soap cure for 4-6 weeks. 4. Hot process is similar to cold process but involves cooking the soap to complete saponification and evaporation before adding ingredients.