I have the same problem. I found that if you take the end of a cuticle stick and scrape underneath it gets out almost everything. And every night before you go to bed dip them in lemon juice and scrub with a nail brush. It takes little effort. It's also easier to keep them clean if you keep them short. And, even if a little something gets under your nails, the white nail polish from the french manicure, or any other color will cover the dirt.
Hope your nails look gorgeous!
P.S. If you use baking soda, it will make your nails weak.How can I keep underneath my nails white?
Dip them in a bowl of lemon juice and scrub with a nail brush dipped in baking soda. Hope i helped:)
Ok, it works because the lemon juice has citric acid, which bleaches, i believe lol. And after you already have the acid on your nails, using the nail brush in baking soda is basically like exfoliating your nails (the brush) and the baking soda is coarse enough to give exfoliation. The baking soda also bleaches as well, (its a main ingriedient in tooth whiteners) so presto, you have white nails!! If you get a chance email me, and tell me if it works:)