It is rare that you might have to replace the Solidoodle's brass nozzle, but if you do here are the instructions concerning the replacement.
Remove Kapton Tape
The thermistor is attached to the nozzle with Kapton tape. It is very important that you take note of the positioning of the kapton tape on the nozzle, as this will affect the temperature readings of the Solidoodle.
If you are not familiar with the thermistor, here is a picture to help:
*picture of thermistor*
From here you should be able to unscrew the nozzle. This is a little more difficult than it seems, as the PEEK plastic barrel may turn with the nozzle as you attempt to unscrew it. If this is causing a problem, wedge a small object between the wooden slat and extruder housing to stop the movement.
Once the nozzle has been removed, take this opportunity to check the inside of your Solidoodle for clogs. Once you are satisfied, you may replace the nozzle
The thermistor must go back in to it's original position and be held in place by Kapton tape. Other tapes will not do for this, as the heat from the nozzle will melt most house hold tapes.
Added 1/2/2013 Gordy McKinney If you do not have the recommended 1/4" Kapton Tape available, I found that I could sitck some wide Kapton (3") on some glass, then use a razor blade to cut my own 1/4" strip. The length (3") was the perfect length to work with when wrapping the nozzle.