Solid soap is a type of cleansing product that comes in a firm, bar form. It is made by combining fats or oils with an alkali, a process known as saponification. Solid soap is effective for cleaning skin and can also be used for washing clothes and dishes. Unlike liquid soap, solid soap often contains fewer preservatives and can be more environmentally friendly due to less packaging. It is available in various scents and formulations, including those made with natural ingredients like essential oils and herbs, catering to different skin types and preferences.