Lemon and olive oil as nail strengtheners - If your nails are turning brittle and yellow by the day, soak them in a soothing mixture of olive oil and lemon. Lemon has strong bleaching properties and could reduce the appearance of yellow stains. Similarly, olive oil moisturises and leaves your nails looking healthier. Take a mid-sized bowl filled with olive oil and squeeze out 4-5 drops of lemon juice to it. Soak in for 7-10 minutes and wash off with lukewarm water.