Nail polish is usually considered hazardous waste due to its solvent content. Take it during the hazardous household waste clean-up days, if your community has them. My city lists nail polish specifically as one of the items to bring.

Small items don’t often get sorted at recycling facilities anyway, so you shouldn’t add nail polish bottles to your recycling. I would suggest reusing them for something if you can figure out what they’d be good for. To clean them out I would suggest swishing nail polish remover inside then using a bottle brush. Maybe they could hold something small or you can do something decorative with them.

Most disposable make-up brushes are made of plastic, which usually ends up in the trash (tiny plastic items like that don’t tend to make it through sorting machines even if they might be labeled recyclable). There are several more sustainable options such as bamboo make up brushes which at least are made from natural materials that are biodegradable.