1) Yellow Nails Natural Treatment
Yellow fingernails are caused most frequently by use of nail polish, smoking and fungus under the nails. As a treatment for yellow fingernails for the first two causes, one must refrain from using polish and smoking.  As for the yellowing fungus, tea tree oil has been demonstrated in two scientific studies to be more effective than common antifungal drugs in clearing up the fungus that causes yellow finger nails.  Bad diet is what allows the fungus to grow in the first place.  Try taking beta glucan as a supplement to strengthen the immune system which then gets rid of the fungus.
 
After bathing, try massaging olive oil or jojoba oil onto your nails.  Be sure to be attentive to your cuticles as well.  This is a very effective natural treatment for weak fingernails.

Jojoba oil

Be sure to avoid a sawing back and forth motion when filing your nails.  Only file your nail in one direction.  This natural treatment is great for keeping fingernails in good health.  It's also a good idea to use an emery board as opposed to a metal nail file. Until your nails are strong, try to keep them short until they are stronger.
 
While especially important after exposing your hands to water, be sure to apply a good quality moisturizer to your hands daily.  This should even be done several times a day as a wonderful natural treatment for fingernail health.
 
For naturally soft hands and healthy nails, try this awesome natural treatment.  Before going to bed, apply a thick layer of moisturizer to your hands and nails.  A great one to try is Un-Petroleum by Alba.  This is just like petroleum jelly, but without petrolatum.  Once the moisturizer is applied, put on some white cotton gloves.  If you don't have any handy, then a pair of white cotton socks will do the trick.  Remove the gloves (or socks) in the morning, and you'll awake to beautiful hands!
 
2) Warm Olive Oil
Once a week, try soaking your nails in warm olive oil.  This natural treatment is great at strengthening brittle fingernails.  You can also add two tablespoons of lemon juice if your nails are stained.  Be sure to skip the lemon juice addition if you have any hangnails or cuts -  these will be irritated by the lemon juice!
 
If you aren't treating your cuticles, then you aren't properly caring for your nails.  To naturally treat your cuticles, use an orange-wood stick to gently push back your cuticle.  Do this once weekly after soaking your nails.  Move the stick in a circular motion, and simply wipe any dead skin away with a cotton ball.  Complete your nail treatment with a good quality moisturizer.  I like to use a combination of shea butter and aloe vera.  You can get an organic version of this online from www dot ocean-lovers dot com.
 
You can naturally treat your fingernails by maintaining a good diet that supplies plenty of nutrients to your  nails.  Be sure that you're getting enough iron, fat, protein, folic acid, vitamins C and B and calcium.  On the other hand, be sure to avoid exposure to chemicals that can be harmful to your fingernails.  Chemicals can not only lead to major changes in the appearance and growth of your nails, but they can also lead to chronic deformities.