If your feet are always darker than the rest of your body, there must be some reason for it. A toning cream or in fact any home remedy to lighten the skin, if it works on the skin of one part of the body, should work on the rest of your body as well. If this is not happening, you need to find out what the cause is and address it. Skin on areas like the hands usually tends to be darker because it is exposed to the sun more than any other part of the body. This might be the case with your feet - if you spend a lot of time in the sun barefoot or with open shoes, your feet will get tanned, and no treatment will make them lighter till the tan goes away. The only solution to this problem is to wear closed shoes.
Constant friction also causes skin to become dark - this is often the case with areas such as the armpits and the groin, and may also be happening with your feet. Try switching to more comfortable shoes for a few months and see if there is any improvement. The best will probably be sports shoes, if they go with your daily clothes - they are least likely to rub against your feet and are of course closed.
answered by G M