This is low use (almost new) 0.60mm brass FDM nozzle. It became plugged and was changed out for a new nozzle. 

The tip is barely worn so this nozzle is worth the little bit of effort to clear and make available for reuse. Some brass nozzles are as low cost as $0.50 to $1.00...  But it is a shame to just toss them away.

In my workshop I have some kiln type firebrick. A nice surface to heat small onjects like this nozzle. I use a small butane click-torch (Mine is called the Blazzer) and heat the plugged nozzle to cherry red color. I am carefull not to get to the brass melting temperature.

The plastic flames up and burns out of the nozzle. Use the oxydizing (fuzzy) part of the torch flame (just out past the sharp inner cone) and not into the reducing inner cone. The plan is to burn out the plastic so we need some excess oxygen in the flame.

I let the nozzle cool for just a few seconds. Then with pliers, grab and quench the still red nozzle into water. This does NOT harrden the brass, but the temperature change-shock and steam burst helps break up any ash in the nozzle. I re-heat the nozzle to dull red, then let air cool.

Back at the work bench, I inspect the now cold burn-out and ream bore using either a steel acupuncture needle or other tool that are usually available with some nozzle kits. It just pokes out any remaining ash and makes sure the hole is fully open. 

This burn-out process is much eaiser than trying to drill-out hard plastic or hand hold (with pliers) a hot nozzle to clear it.

I end up with a very serviceable clean nozzle.

The lead picture displays the plugged un-treated nozzle,

This is the same nozzle, now cool after the burn out.

This photo, I have polished the tip by rubbing tip on ordinary note paper.

Closser look may show a tiny bit of ash in nozzle. Eaisly removed with little effort.

Compare to fresh new nozzles. For use another time when restoring can't be done.