All hotends can clog at times, and all-metal hotends can be more prone to clogging with PLA. There are "cleaning filaments" that can help to remove small clogs and debris. 

The simplest way to clear a clog in the heat break of any all-metal hotend is to perform a cold pull or atomic pull

If that doesn't work, the Mosquito™ and Copperhead™ Hotends have been designed with high temperature materials in mind. Remove the hot block and heat break from the heat sink. Place the hot block and heat break into an oven or kiln (not one used for food consumption) preheated to 100°C above the melting temperature of the plastic. The goal is to incinerate the plastic. Please do not put the heat sink in the oven. It will deform. Also, please do not burn yourself.