I research pretty much all of the ingredients I incorporate into my bath and body formulations. I'd like to share with you a little of what I've learned, continue reading if you have an interest.
Activated Charcoal:
To become "activated," the charcoal goes through a high temperature steam activation process.  This process increases its surface area, which increases the charcoal's ability to absorb and filter.  This makes activated charcoal the proper choice for medical and cosmetic use.  Activated charcoal is fantastic for oily skin.  Its ability to absorb oil and dirt from pores leaves skin feeling balanced.  If you have dry skin, activated charcoal may be a little bit too drying.  It has been said that activated charcoal is most beneficial for skin by drawing oil, dirt and other harmful substances from clogged pores due to its absorption powers.  One great thing about activated charcol is that even as it cleans and exfoliates your skin it doesn't strip your skin of its natral oils.


Carrot Powder:
Carrot powder is thought to repair and tone the skin, reduce wrinkles and scars, improves circulation, increases elasticity and provides the skin with beta carotene which is an antioxidant.  It contains many vitamins and minerals which is thought to nourish your skin: Vitamins A, B1, B2, B3, B6, B12, C, E, K, Calcium, Iron, Potassium, Phospheros and magnesium.


Sodium Borate (Borax):
Borax is a natural mineral which is widely used as a detergent in the cosmetic industry. Borax naturally occurs from the repeated evaporation of seasonal lakes. Borax is found in creams, lotions, shampoos, gels, bath salts, and bath bombs. It is an emulsifier, preservative, cleansing agent, and a buffering agent. Borax has the ability to soften the water, and suspend soap particles in the bath water. The result is soft, clean, and healthy skin, which is not clogged by the residue of soap particles. When used in combination with citric acid in bath bombs or bath salt recipes, the product will produce a fizzing action. It stores well under any condition, but extreme moisture is to be avoided. Avoid contact with the eyes and mouth, and do not expose directly to the skin. Can be used directly for cleaning purposes, and is suitable for both cosmetic and cleaning formulations. Borax has an effectiveness often compared to oxy clean. It produces a basic solution in water which increases the effectiveness of cleaners. It can be used to make handmade laundry soap formulations, and to create handmade toilet and dishwasher tabs .

(Resources: Mountain Rose Herbs; Wholesale Supplies Plus, Nature's Garden)

Sodium Carbonate (Washing Soda): 
Carbonate is a sodium salt of carbonic acid. Extracted from the ashes of plants growing in sodium rich soils. It works as an excellent stain remover and is sometimes used as a water softener.

Wholesale Supplies Plus, Wikipedia)

Sage Leaf:
Sage is used in skincare products and in soap as an astringent and to relieve itching. Sage has also been said to whiten teeth and has been used in this manner for many years in other cultures. I strongly recommend that you consult with a qualified health care provider before using or consuming any herbal products while pregnant or nursing or on any medications.

DIY Natural., Nature's Garden, Wikipedia)