The best way I've found yet is pads soaked in nail polish remover, held in place with tinfoil, but still takes ages, and patience is not one of my greatest gifts...
Don't want to stop using it as it's finally stopping me from biting them, but surely there is an easier way of getting it off when it starts to get tatty?
Happy to be told I am a muppet if I'm missing the blindingly obvious !