I need to clean small quartz tubing (I.D. = .035" O.D. = .069") that is sealed at one end.
Alconox, Inc recommends Liquinox, a mild alkaline cleaner that is phosphate free. Since the ID is a little less than 1 mm, rinsing will be a bit tricky. The ideal cleaning scenario would be to use a syringe inserted up into the end of the tube, first flushing with warm 1% Liquinox, followed by adequate amounts of rinsing with DI water. If this is not practical, as long as the tube is not too long (less than 6 mm) then if soaked upright in ultrasonics, would probably work but an adequate rinse must be carried out as well using the ultrasonic tank.
Click here for Liquinox technical bulletin.