You can't go wrong with The Inkey List PHA Toner (£10), which is a simple and supremely gentle exfoliating toner that contains polyhydroxy acid. A favourite of a few POPSUGAR editors, even those with the most finicky of skin can use it on a daily basis due to the fact that it's not he least bit irritating (although, always make sure to do a patch test if you have very sensitive skin) and plays nicely with pretty much every serum and cream we've applied on top of it.