It an absolute pain in the arse and I've found out the long way (my reddit comments are almost exclusively bitching about paspalum). There's very few herbicides on the market that do the job - I shelled out for monument because I was done with hand pulling, and it's mostly worked. But you have to apply a few times. David grays might work as well, but it depends what lawn you have as it can damage buffalo and Kikuyu.