Sorry, I'm an intruder in Style & Beauty but I think you'll have the best advice. I've reached that age when vertical ridges develop in your fingernails and one has started to split. I keep it clipped as short as possible and try to file the ridges out but the split is moving down into the nail bed. I'll have to cover it with a plaster to stop it catching but is there any thing I can do to sort it out?