Mix: How to clean public/css and /public/js folder when using version() ?

I'm using Laravel 5.4 and mix.

mix
    .js('resources/assets/js/model.js', 'public/js')
    .js('resources/assets/js/family.js', 'public/js')
    .js('resources/assets/js/home.js', 'public/js')
    .js('resources/assets/js/app.js', 'public/js')
    .extract(['vue', 'lodash', 'vue-resource', 'vue-carousel'])
    .sass('resources/assets/sass/app.scss', 'public/css')
    .sass('node_modules/font-awesome/scss/font-awesome.scss', 'public/css/vendor')
    .version();

The problem is that public/css is full of trash after a lot of npm run watch-poll.

Is there a way to keep it cleaned? I tried to add as first instruction .remove(['public/css', 'public/js])` (like in mix Elixir/mix for 5.3) but it doesn't work